A083006 Numbers k such that Sum_{j=0..k-1} Bernoulli(j)*binomial(k,j)^2 is an integer.

0, 1, 2, 3, 4, 6, 8, 10, 12, 24, 28, 30, 36, 40, 60, 108, 120

Offset

1,3

Comments

Next term, if it exists, is > 2500.

No further terms up to 5000. - Harvey P. Dale, Nov 14 2011

No further terms up to 10000. - Vaclav Kotesovec, Jun 07 2019

Links

Table of n, a(n) for n=1..17.

Index entries for sequences related to Bernoulli numbers.

Maple

p:=proc(n) if type(add(bernoulli(k)*binomial(n, k)^2, k=0..n-1), integer) then n else fi end: seq(p(n), n=0..200); # Emeric Deutsch, Mar 19 2005

Mathematica

Select[Range[0, 150], IntegerQ[Sum[BernoulliB[k]Binomial[#, k]^2, {k, 0, #-1}]]&] (* Harvey P. Dale, Nov 14 2011 *)

Prog

(PARI) isok(k) = denominator(sum(j=0, k-1, bernfrac(j)*binomial(k, j)^2)) == 1; \\ Michel Marcus, Feb 15 2021

Crossrefs

Sequence in context: A061953 A029517 A177907 * A352929 A096061 A100919

Adjacent sequences: A083003 A083004 A083005 * A083007 A083008 A083009

Keyword

more,nonn

Author

Benoit Cloitre, May 31 2003

Status

approved