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## #26 2011-05-19 08:22:08

John E. Franklin
Member
Registered: 2005-08-29
Posts: 3,582

### Re: Let's make triangular numbers.

351
a triangle with 26 rows, pair them up for 13 pairs of 27.
270 + 81 = 351, yup.

igloo myrtilles fourmis

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## #27 2011-05-19 14:41:09

bobbym
From: Bumpkinland
Registered: 2009-04-12
Posts: 90,883

### Re: Let's make triangular numbers.

378

Is the sum of two other traingular numbers.

378 = Triangular(12) + Triangular(24)

In mathematics, you don't understand things. You just get used to them.

I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.

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## #28 2011-05-25 00:02:10

bob bundy
Moderator
Registered: 2010-06-20
Posts: 6,538

### Re: Let's make triangular numbers.

I see what youre up to here.

Everyone is holding off from posting because you all want to hit post #31.

So Im going to have it this way.

The North Circular Road around  inner London = 406

Bob

You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei

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## #29 2011-05-25 00:04:40

bob bundy
Moderator
Registered: 2010-06-20
Posts: 6,538

### Re: Let's make triangular numbers.

Then

(root(4) x 10 + (4 + 5)) x 3 x 5 = 435

Bob

You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei

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## #30 2011-05-25 00:06:44

bob bundy
Moderator
Registered: 2010-06-20
Posts: 6,538

### Re: Let's make triangular numbers.

Triangular  45 with a triangular 6 between = 465

Bob

You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei

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## #31 2011-05-25 00:08:01

bob bundy
Moderator
Registered: 2010-06-20
Posts: 6,538

### Re: Let's make triangular numbers.

496  Arrrrhh!  Thats perfect!

Bob

You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei

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## #32 2011-05-25 02:56:40

bobbym
From: Bumpkinland
Registered: 2009-04-12
Posts: 90,883

### Re: Let's make triangular numbers.

528

2^9 + 2^4 = 528

In mathematics, you don't understand things. You just get used to them.

I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.

Online

## #33 2011-05-25 08:29:05

anonimnystefy
Real Member
From: The Foundation
Registered: 2011-05-23
Posts: 15,673

### Re: Let's make triangular numbers.

561

if HCF(561,b)=1 then b^560 is congruent to 1 modulo 561

Last edited by anonimnystefy (2011-08-14 22:39:57)

Here lies the reader who will never open this book. He is forever dead.

Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and Punishment

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## #34 2011-05-25 09:10:04

bobbym
From: Bumpkinland
Registered: 2009-04-12
Posts: 90,883

### Re: Let's make triangular numbers.

595

In mathematics, you don't understand things. You just get used to them.

I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.

Online

## #35 2011-05-25 09:15:28

anonimnystefy
Real Member
From: The Foundation
Registered: 2011-05-23
Posts: 15,673

### Re: Let's make triangular numbers.

630=2*3*3*5*7=97+101+103+107+109+113 which are consecutive primes

Here lies the reader who will never open this book. He is forever dead.

Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and Punishment

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## #36 2011-05-25 09:50:48

bobbym
From: Bumpkinland
Registered: 2009-04-12
Posts: 90,883

### Re: Let's make triangular numbers.

666

The mark of the beast.

In mathematics, you don't understand things. You just get used to them.

I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.

Online

## #37 2011-05-25 22:19:21

anonimnystefy
Real Member
From: The Foundation
Registered: 2011-05-23
Posts: 15,673

### Re: Let's make triangular numbers.

703-a Kaprekar number

Last edited by anonimnystefy (2011-05-25 22:22:06)

Here lies the reader who will never open this book. He is forever dead.

Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and Punishment

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## #38 2011-08-14 09:28:39

anonimnystefy
Real Member
From: The Foundation
Registered: 2011-05-23
Posts: 15,673

### Re: Let's make triangular numbers.

740-a non-totient number

Here lies the reader who will never open this book. He is forever dead.

Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and Punishment

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## #39 2011-08-14 18:34:26

bobbym
From: Bumpkinland
Registered: 2009-04-12
Posts: 90,883

### Re: Let's make triangular numbers.

Hi;

741 a triangular number.

In mathematics, you don't understand things. You just get used to them.

I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.

Online

## #40 2011-08-14 22:34:40

anonimnystefy
Real Member
From: The Foundation
Registered: 2011-05-23
Posts: 15,673

### Re: Let's make triangular numbers.

oh yes you are right

catching up:
780-also a hexagonal number,Harshad number,sum of ten consecutive primes:

780=59 + 61 + 67 + 71 + 73 + 79 + 83 + 89 + 97 + 101

8+2+0|820

Here lies the reader who will never open this book. He is forever dead.

Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and Punishment

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## #41 2012-07-04 04:58:55

John E. Franklin
Member
Registered: 2005-08-29
Posts: 3,582

### Re: Let's make triangular numbers.

861 = 41 + 820

41 by 21 = 800 + 1 + 40 + 20

igloo myrtilles fourmis

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## #42 2012-07-04 05:24:12

bobbym
From: Bumpkinland
Registered: 2009-04-12
Posts: 90,883

### Re: Let's make triangular numbers.

Hi;

903 not a prime.

In mathematics, you don't understand things. You just get used to them.

I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.

Online

## #43 2012-07-04 05:27:26

anonimnystefy
Real Member
From: The Foundation
Registered: 2011-05-23
Posts: 15,673

### Re: Let's make triangular numbers.

946-not a prime either.

Here lies the reader who will never open this book. He is forever dead.

Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and Punishment

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## #44 2012-07-04 05:29:22

bobbym
From: Bumpkinland
Registered: 2009-04-12
Posts: 90,883

### Re: Let's make triangular numbers.

990 almost a prime.

In mathematics, you don't understand things. You just get used to them.

I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.

Online

## #45 2012-07-04 05:33:24

anonimnystefy
Real Member
From: The Foundation
Registered: 2011-05-23
Posts: 15,673

### Re: Let's make triangular numbers.

1035-first triangular number greater than 1000.

Here lies the reader who will never open this book. He is forever dead.

Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and Punishment

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## #46 2012-07-04 05:36:30

bobbym
From: Bumpkinland
Registered: 2009-04-12
Posts: 90,883

### Re: Let's make triangular numbers.

1081 also not a prime.

In mathematics, you don't understand things. You just get used to them.

I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.

Online

## #47 2012-07-04 05:40:46

anonimnystefy
Real Member
From: The Foundation
Registered: 2011-05-23
Posts: 15,673

### Re: Let's make triangular numbers.

1128-not not a not-prime

Here lies the reader who will never open this book. He is forever dead.

Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and Punishment

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## #48 2012-07-04 05:42:33

bobbym
From: Bumpkinland
Registered: 2009-04-12
Posts: 90,883

### Re: Let's make triangular numbers.

1176 add 600 and it has meaning today!

In mathematics, you don't understand things. You just get used to them.

I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.

Online

## #49 2012-12-13 18:10:59

mathaholic
Member
From: Juliania
Registered: 2012-11-29
Posts: 2,896
Website

### Re: Let's make triangular numbers.

"What is the square root of 2? 1.4141592653589793238" Seriously, I thought it was that. Too round?
3.141592653589793238...

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## #50 2012-12-13 20:44:41

bobbym
From: Bumpkinland
Registered: 2009-04-12
Posts: 90,883

### Re: Let's make triangular numbers.

The next triangular number is 1275.

In mathematics, you don't understand things. You just get used to them.

I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.

Online