Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ π -¹ ² ³ °

You are not logged in.

- Topics: Active | Unanswered

Pages: **1**

**wintersolstice****Real Member**- Registered: 2009-06-06
- Posts: 125

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...!!!

Offline

**ganesh****Administrator**- Registered: 2005-06-28
- Posts: 23,064

What are happy primes?

It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Offline

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

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.

Offline

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

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

Offline

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

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.

Offline

**bobbym****bumpkin**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606

Hi Rick;

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

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.**** Always satisfy the Prime Directive of getting the right answer above all else.**

Offline

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

For bobbym

Quote:

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

RickIsAnIdiot

Thanks bobbym! keep up the good work..

Offline

**bobbym****bumpkin**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606

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.****If it ain't broke, fix it until it is.**** Always satisfy the Prime Directive of getting the right answer above all else.**

Offline

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

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)*

Offline

**bobbym****bumpkin**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606

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.****If it ain't broke, fix it until it is.**** Always satisfy the Prime Directive of getting the right answer above all else.**

Offline

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

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?)

Offline

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

Has Anyone Heard of "DRACULA" Numbers!

Offline

Pages: **1**