login
This site is supported by donations to The OEIS Foundation.

 

Logo

Annual appeal: Please make a donation to keep the OEIS running! Over 6000 articles have referenced us, often saying "we discovered this result with the help of the OEIS".
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A094756 a(n) = least k>1 such that (1+2+3+...+k) divides (1^n + 2^n + 3^n + ... + k^n). 2
2, 4, 2, 7, 2, 4, 2, 7, 2, 4, 2, 16, 2, 4, 2, 7, 2, 4, 2, 7, 2, 4, 2, 16, 2, 4, 2, 7, 2, 4, 2, 7, 2, 4, 2, 16, 2, 4, 2, 7, 2, 4, 2, 7, 2, 4, 2, 22, 2, 4, 2, 7, 2, 4, 2, 7, 2, 4, 2, 16, 2, 4, 2, 7, 2, 4, 2, 7, 2, 4, 2, 16, 2, 4, 2, 7, 2, 4, 2, 7, 2, 4, 2, 16, 2, 4, 2, 7, 2, 4, 2, 7, 2, 4, 2, 22, 2, 4, 2, 7, 2, 4 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..102.

FORMULA

Formulae from Don Reble: If N is not divisible by 2, a(N) = 2.

Otherwise, if N is not divisible by 4, a(N) = 4.

Otherwise, if N is not divisible by 12, a(N) = 7.

Otherwise, if N is not divisible by 48, a(N) = 16.

Otherwise, if N is not divisible by 240, a(N) = 22 or 31. (31 if N is divisible by 528=11*48; otherwise 22).

Otherwise, if N is not divisible by 720, a(N) = 37.

Otherwise, if N is not divisible by 11 nor 23, a(N) = 46.

Otherwise, if N is not divisible by 77, a(N) = 58.

Otherwise, if N is not divisible by 13 nor 53, a(N) = 106.

Otherwise, if N is not divisible by 13, a(N) = 157.

Otherwise, if N is not divisible by 41 nor 83, a(N) = 166. ...

That works for N < 29549520 or so. But it is unlikely that any finite description of that kind is complete.

MATHEMATICA

f[n_] := Block[{k = 2}, While[ !IntegerQ[ 2Sum[i^n, {i, k}]/(k(k + 1))], k++ ]; k]; Table[ f[n], {n, 50}] (* Robert G. Wilson v, Jun 02 2004 *)

CROSSREFS

Cf. A094755.

Sequence in context: A261964 A177847 A021416 * A228367 A110925 A214789

Adjacent sequences:  A094753 A094754 A094755 * A094757 A094758 A094759

KEYWORD

nonn

AUTHOR

Amarnath Murthy, May 29 2004

EXTENSIONS

Edited and extended by Don Reble and Robert G. Wilson v, Jun 02 2004

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified November 20 08:12 EST 2017. Contains 294962 sequences.