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 A295231 #21 Nov 18 2017 13:13:47
%S A295231 -4,15,765,61425,1214325,95893875,2615987248875,298915241625,
%T A295231 10670785663663125,10218227413637368125,1605716856726047690625,
%U A295231 56404413605424162403125,3387648475383059302662121875,744538093174369303262578125
%N A295231 Numerators of (-1)^(n+1) * (2*n)! * (2^(2*n)+1)/(B_{2*n} * 2^(4*n-1)), where B_{n} is the Bernoulli number.
%C A295231 Pi^(2*n) > a(n)/A295232(n) for n > 0.
%H A295231 Seiichi Manyama, <a href="/A295231/b295231.txt">Table of n, a(n) for n = 0..223</a>
%e A295231 Zeta(2) = Pi^2/6 > 1 + 1/2^2, so Pi^2 > 15/2.
%e A295231 Zeta(4) = Pi^4/90 > 1 + 1/2^4, so Pi^4 > 765/8.
%e A295231 Zeta(6) = Pi^6/945 > 1 + 1/2^6, so Pi^6 > 61425/64.
%o A295231 (PARI) {a(n) = numerator((-1)^(n+1)*(2*n)!*(2^(2*n)+1)/(bernfrac(2*n)*2^(4*n-1)))}
%Y A295231 Cf. A002432/A046988, A295232 (denominators).
%K A295231 sign,frac
%O A295231 0,1
%A A295231 _Seiichi Manyama_, Nov 18 2017