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 A165949 #10 May 04 2019 23:07:24 %S A165949 1,1,7,1,11,91,1,17,133,11,23,91,1,29,2387,17,1,63973,1,451,301,23,47, %T A165949 1547,11,53,133,29,59,1892891,1,17,10787,1,781,4670029,1,1,553,7667, %U A165949 83,113477,1,2047,45353,47,1,150059,1,1111,721,53,107,6973057,253,55709,7 %N A165949 a(n) = A027762(n)/A165734(n). %p A165949 A165734 := proc(n) op( 1+(n mod 2),[30,6]) ; end: %p A165949 A027762 := proc(n) a := 0 ; p := 2 ; while p-1 <= 2*n do if (2*n) mod (p-1) = 0 then a := a+1/p ; fi; p := nextprime(p) ; od: denom(a) ; end: %p A165949 A165949 := proc(n) A027762(n)/A165734(n) ; end: seq(A165949(n),n=1..80) ; # _R. J. Mathar_, Oct 05 2009 %t A165949 a[n_] := Numerator[ Denominator[ BernoulliB[2*n, 1/2]]/(3*5*2^(2*n))]; Array[a, 57] (* _Jean-François Alcover_, Apr 17 2013, after _Paul Curtz_ *) %Y A165949 Cf. A124886. %K A165949 nonn %O A165949 1,3 %A A165949 _Paul Curtz_, Oct 01 2009 %E A165949 Extended by _R. J. Mathar_, Oct 05 2009