Math Is Fun Forum

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

You are not logged in.

#1 2015-10-16 03:16:32

phanthanhtom
Member
Registered: 2012-06-22
Posts: 290

Order the integers from 1 to 37

Order the integers from 1 to 37 in a sequence such that the sum of the first n numbers is divisible by the (n+1)th number.

a) If the first integer is 37 and the second integer is 1, how many possible sequences are there?

b) How many possible sequences are there? (in general)

If there is less than 50 sequences for a, please list them for me.

Thanks.

Offline

#2 2015-10-21 02:38:48

Agnishom
Real Member
From: Riemann Sphere
Registered: 2011-01-29
Posts: 24,974
Website

Re: Order the integers from 1 to 37

Interesting problem.


'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
I'm not crazy, my mother had me tested.

Offline

#3 2015-10-21 03:06:47

Agnishom
Real Member
From: Riemann Sphere
Registered: 2011-01-29
Posts: 24,974
Website

Re: Order the integers from 1 to 37

The number for b is very large


'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
I'm not crazy, my mother had me tested.

Offline

#4 2015-10-21 13:15:34

phanthanhtom
Member
Registered: 2012-06-22
Posts: 290

Re: Order the integers from 1 to 37

Yeah, I guessed it.

Have you programmed it and get an answer?

Offline

#5 2015-10-21 13:25:48

Agnishom
Real Member
From: Riemann Sphere
Registered: 2011-01-29
Posts: 24,974
Website

Re: Order the integers from 1 to 37

Actually, I couldn't. It takes forever


'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
I'm not crazy, my mother had me tested.

Offline

#6 2015-10-21 22:37:03

phanthanhtom
Member
Registered: 2012-06-22
Posts: 290

Re: Order the integers from 1 to 37

Explain?

Offline

#7 2015-10-21 23:24:47

Agnishom
Real Member
From: Riemann Sphere
Registered: 2011-01-29
Posts: 24,974
Website

Re: Order the integers from 1 to 37

The program is taking too long to produce all the answers. I'll ask bobbym for help


'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
I'm not crazy, my mother had me tested.

Offline

#8 2015-10-21 23:25:54

phanthanhtom
Member
Registered: 2012-06-22
Posts: 290

Re: Order the integers from 1 to 37

Okay. Is there a better way to count them?

I mean, there should be a way to compute the number of permutations without listing all those permutations out, right?

Offline

#9 2015-10-22 16:31:55

Agnishom
Real Member
From: Riemann Sphere
Registered: 2011-01-29
Posts: 24,974
Website

Re: Order the integers from 1 to 37

I am not listing out all permutations. I am determining what the possible right most number could be, every time.

FYI, I can calculate upto 20.

Last edited by Agnishom (2015-10-22 18:38:40)


'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
I'm not crazy, my mother had me tested.

Offline

Board footer

Powered by FluxBB