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 A335751 #10 Jun 21 2020 06:01:47 %S A335751 2,6,15,63,225,693,1289925,4455,34459425,808782975,5685805125, %T A335751 4106936925,18767808934875,72977109975,491292329653125, %U A335751 305714614450620375,1578522255175490625,33864491287501875,6076788748684677645496875,34996278233163121875,55478375013295336399171875 %N A335751 a(n) = denominator(Bernoulli(2*n)*(1/2 - n)! / sqrt(Pi)). %F A335751 a(n) = denominator(-2*n*Zeta(1 - 2*n)*(1/2 - n)! / sqrt(Pi)) for n >= 1. %e A335751 r(n) = 1/2, 1/6, 1/15, 2/63, 4/225, 8/693, 11056/1289925, 32/4455, ... %p A335751 a := n -> bernoulli(2*n)*(1/2 - n)! / sqrt(Pi): %p A335751 seq(denom(simplify(a(n))), n = 0..21); %Y A335751 Cf. A335750 (numerator), A000367/A002445, A004193. %K A335751 nonn,frac %O A335751 0,1 %A A335751 _Peter Luschny_, Jun 20 2020