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#1 2009-06-07 23:37:40

wintersolstice
Real Member
Registered: 2009-06-06
Posts: 114

seven and thirteen

7 and 13 are the first two happy primes and 91 (7×13) is also a happy number. this means that 19 is happy, this is the 3rd happy prime!


Why did the chicken cross the Mobius Band?
To get to the other ...um...!!!

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#2 2009-06-08 00:00:11

ganesh
Moderator
Registered: 2005-06-28
Posts: 14,818

Re: seven and thirteen

What are happy primes?


Character is who you are when no one is looking.

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#3 2009-06-08 00:33:47

mathsyperson
Moderator
Registered: 2005-06-22
Posts: 4,900

Re: seven and thirteen

Happy numbers are related to a sequence where each term is determined by the sum of the squares of the previous term's digits. eg.

7
49 (= 7²)
97 (= 4² + 9²)
130
10
1
1
1
...


A happy number is a number that initiates a sequence that goes to 1, like 7 does above.

An unhappy number will instead eventually fall into the following loop:
4, 16, 37, 58, 89, 145, 42, 20, 4...


Why did the vector cross the road?
It wanted to be normal.

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#4 2009-06-09 18:36:13

DarkLightA
Member
Registered: 2009-05-27
Posts: 16

Re: seven and thirteen

Hmm.. Never heard of this.. Is there a use for this sequence?

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#5 2009-06-13 02:59:52

RickIsAnIdiot
Member
Registered: 2009-06-13
Posts: 5

Re: seven and thirteen

Happy numbers are related to a sequence where each term is determined by the sum of the squares of the previous term's digits. eg.

7
49 (= 7²)
97 (= 4² + 9²)
130
10
1
1
1
...
For mathsyperson
Quote:

A happy number is a number that initiates a sequence that goes to 1, like 7 does above.

An unhappy number will instead eventually fall into the following loop:
4, 16, 37, 58, 89, 145, 42, 20, 4...

RickIsAnIdiot

Do you have any more Happy Number examples.

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#6 2009-06-13 03:07:17

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 88,762

Re: seven and thirteen

Hi Rick;

http://en.wikipedia.org/wiki/Happy_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.

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#7 2009-06-14 00:37:05

RickIsAnIdiot
Member
Registered: 2009-06-13
Posts: 5

Re: seven and thirteen

For bobbym
Quote:

http://en.wikipedia.org/wiki/Happy_number

RickIsAnIdiot

Thanks bobbym! keep up the good work..

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#8 2009-06-14 01:23:58

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 88,762

Re: seven and thirteen

Hi Rick;

Please don't be offended but I don't feel comfortable calling anyone an idiot so may I call you Rick. Anyway welcome to the forum.

Last edited by bobbym (2009-06-14 01:43:15)


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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#9 2009-06-16 00:11:58

RickyIsAnIdiot
Banned
Registered: 2009-06-15
Posts: 18

Re: seven and thirteen

For bobbym
Quote:
Hi Rick;

Please don't be offended but I don't feel comfortable calling anyone an idiot so may I call you Rick. Anyway welcome to the forum.

RickyIsAnIdiot

That's OK! you can call me Rick,#ick,#rick it's only names? Knowing the meaning's is the main thing...

Last edited by RickyIsAnIdiot (2009-06-16 00:13:47)

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#10 2009-06-16 03:09:06

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 88,762

Re: seven and thirteen

That's OK! you can call me Rick,#ick,#rick it's only names? Knowing the meaning's is the main thing...

I don't appreciate what you are trying to do here. The meaning... what are you implying?

Last edited by bobbym (2009-06-16 05:11:49)


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

#11 2009-06-17 00:22:18

Kurre
Member
Registered: 2006-07-18
Posts: 280

Re: seven and thirteen

There are two different accounts posting here, both RICKisanidiot and RICKYisanidiot, imo a clear violence to the multiple account rule (which I think exist on this forum?)

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#12 2009-06-17 04:37:47

RickyIsAnIdiot
Banned
Registered: 2009-06-15
Posts: 18

Re: seven and thirteen

Has Anyone Heard of "DRACULA" Numbers!

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