This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A081739 #12 May 03 2025 07:45:56 %S A081739 0,0,452,481832565076,3336994692120829058949545155598207748188, %T A081739 4183667308477313795108662587270037418426429056133620947343416969739965511482242658521291610836247844507748569589344 %N A081739 a(n) = (-1/2^n)*(A000367(2^n)+1). %F A081739 a(n) = A076547(n)-1 (Conjecture). - _R. J. Mathar_, Apr 22 2007 %t A081739 a[n_] := -(Numerator[BernoulliB[2^(n+1)]] + 1)/2^n; Array[a, 6] (* _Amiram Eldar_, May 03 2025 *) %o A081739 (PARI) a(n) = -(numerator(bernfrac(1 << (n+1))) + 1) >> n; \\ _Amiram Eldar_, May 03 2025 %Y A081739 Cf. A000367, A076547. %K A081739 nonn %O A081739 1,3 %A A081739 _Benoit Cloitre_, Apr 06 2003