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#1 2011-03-02 01:55:32

John E. Franklin
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Let's make triangular numbers.

The first triangular number is 1.
To continue this thread, simply
add 2, then 3, then 4, on forever
to make triangular numbers.

So I'll go first:

1
(one)


igloo myrtilles fourmis
 

#2 2011-03-02 12:28:07

bobbym
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Re: Let's make triangular numbers.

3 is triangular and prime.


In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.
 

#3 2011-03-03 04:17:16

G-man
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Re: Let's make triangular numbers.

6  Its triangular & first composite which isn't a square.


Maths!......sleep
 

#4 2011-03-03 08:41:30

bobbym
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Re: Let's make triangular numbers.

10 - The number of balls in a 10 ball rack. The first 2 digit triangular number! Also it is larger than 1 - 9 and has a zero in it.


In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.
 

#5 2011-03-03 11:31:13

John E. Franklin
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Re: Let's make triangular numbers.

15
  5 x (6/2)


igloo myrtilles fourmis
 

#6 2011-03-03 14:17:51

bobbym
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Re: Let's make triangular numbers.

21 everybody's favorite number


In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.
 

#7 2011-03-03 14:43:46

MathsIsFun
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Re: Let's make triangular numbers.

28: has factors 1, 2, 4, 7, 14, 28 and reminds me of February


"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman
 

#8 2011-03-03 14:53:48

G-man
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Re: Let's make triangular numbers.

36
square of product of first two consecutive primes.


Maths!......sleep
 

#9 2011-03-03 20:13:39

bobbym
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Re: Let's make triangular numbers.

45 - ( Colt ) the best automatic ever made.


In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.
 

#10 2011-03-04 14:53:14

G-man
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Re: Let's make triangular numbers.

55..........dunno


Maths!......sleep
 

#11 2011-03-04 17:17:35

bobbym
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Re: Let's make triangular numbers.

66 - the 11 the triangular number and the name of a now infamous highway here in the southwest.


In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.
 

#12 2011-03-07 01:21:55

matthen
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Re: Let's make triangular numbers.

78

note these triangular numbers go:
...,45,55,66,78,91, quite cool that 4,5,6,7,8,9 appear in order with no interruptions!

 

#13 2011-03-07 04:49:43

bobbym
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Re: Let's make triangular numbers.

91 The most powerful triangular number and the one that wants to be a square the most. Also it is the only one that is 7 * 13.


In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.
 

#14 2011-03-23 10:31:19

John E. Franklin
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Re: Let's make triangular numbers.

105=14+91     
(14/2)*15


igloo myrtilles fourmis
 

#15 2011-03-23 11:48:39

bobbym
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Re: Let's make triangular numbers.

The 15th triangular number is 120. Which is also 5!.


In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.
 

#16 2011-03-23 12:58:55

G-man
Member

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Re: Let's make triangular numbers.

136.........1, 3 & 6 are first 3 triangle numbers.


Maths!......sleep
 

#17 2011-03-23 13:28:21

bobbym
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Re: Let's make triangular numbers.

153

Is a square away from 2 squares. 12^2 + 3^3 = 153 and 13^2 - 4^2 = 153


In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.
 

#18 2011-04-06 00:21:55

John E. Franklin
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Re: Let's make triangular numbers.

171
     153 + 18 = 171
     (19 x 18) / 2


igloo myrtilles fourmis
 

#19 2011-04-06 00:50:56

bobbym
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Re: Let's make triangular numbers.

190

The famous 190 Bowery St.

http://nymag.com/realestate/vu/2008/09/50481/


In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.
 

#20 2011-04-17 06:29:10

John E. Franklin
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Re: Let's make triangular numbers.

210
    210 = 190 + 20
       210 = 14 x 15 = (21 x 20) / 2 on this post # 20.


igloo myrtilles fourmis
 

#21 2011-04-17 06:51:43

bobbym
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Re: Let's make triangular numbers.

231

One of the permutations of 123.


In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.
 

#22 2011-04-17 09:34:54

John E. Franklin
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Re: Let's make triangular numbers.

253
   253 = 231 + 22 = (1 + 22)+(2 + 21)+...(9 + 14)+(10 + 13)+(11 + 12)
                          = 11 x 23 = (23 x 22) / 2
             This triangular number can form a digital triangle with 22 rows in 3 angles differing by 120 degrees.


igloo myrtilles fourmis
 

#23 2011-04-17 12:40:42

bobbym
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Re: Let's make triangular numbers.

276



And that is real close to 253.


In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.
 

#24 2011-04-18 10:13:04

John E. Franklin
Star Member

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Re: Let's make triangular numbers.

300

     Yeah 300!!!!   276 + 24.    (25 x 24) / 2       A triangle with 24 rows.


igloo myrtilles fourmis
 

#25 2011-04-18 10:20:22

bobbym
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Re: Let's make triangular numbers.

325 which is 3*5 - 2 = 13.


In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.
 

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