A081739 a(n) = (-1/2^n)*(A000367(2^n)+1).

0, 0, 452, 481832565076, 3336994692120829058949545155598207748188, 4183667308477313795108662587270037418426429056133620947343416969739965511482242658521291610836247844507748569589344

Offset

1,3

Links

Table of n, a(n) for n=1..6.

Formula

a(n) = A076547(n)-1 (Conjecture). - R. J. Mathar, Apr 22 2007

Mathematica

a[n_] := -(Numerator[BernoulliB[2^(n+1)]] + 1)/2^n; Array[a, 6] (* Amiram Eldar, May 03 2025 *)

Prog

(PARI) a(n) = -(numerator(bernfrac(1 << (n+1))) + 1) >> n; \\ Amiram Eldar, May 03 2025

Crossrefs

Cf. A000367, A076547.

Sequence in context: A233237 A233111 A233215 * A245946 A076547 A365619

Adjacent sequences: A081736 A081737 A081738 * A081740 A081741 A081742

Keyword

nonn

Author

Benoit Cloitre, Apr 06 2003

Status

approved