A341436 Numbers k such that k divides Sum_{j=1..k} j^(k+1-j).

1, 5, 16, 208, 688, 784, 2864, 9555, 17776, 81239

Offset

1,2

Comments

Numbers k such that k divides A003101(k).

a(11) > 10^5.

Links

Table of n, a(n) for n=1..10.

Example

1^5 + 2^4 + 3^3 + 4^2 + 5^1 = 65 = 5 * 13. So 5 is a term.

Mathematica

Do[If[Mod[Sum[PowerMod[k, n + 1 - k, n], {k, 1, n}], n] == 0, Print[n]], {n, 1, 3000}] (* Vaclav Kotesovec, Feb 12 2021 *)

Prog

(PARI) isok(n) = sum(k=1, n, Mod(k, n)^(n+1-k))==0;

Crossrefs

Cf. A003101, A128981, A188775, A341437.

Sequence in context: A307953 A304762 A317460 * A263906 A160739 A092679

Adjacent sequences: A341433 A341434 A341435 * A341437 A341438 A341439

Keyword

nonn,more

Author

Seiichi Manyama, Feb 11 2021

Status

approved