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 A276595 #32 Jul 15 2018 13:49:17
%S A276595 24,1440,60480,2419200,95800320,2615348736000,149448499200,
%T A276595 21341245685760000,10218188434341888000,1605715325396582400000,
%U A276595 28202200078783610880000,3387648273463487338905600000,372269041039943663616000000,75786531374911731038945280000000
%N A276595 Denominator of the rational part of the sum of reciprocals of even powers of even numbers, i.e., Sum_{k>=1} 1/(2*k)^(2*n).
%C A276595 Denominator of Bernoulli(2*n)/(2*(2*n)!). - _Robert Israel_, Sep 18 2016
%H A276595 Robert Israel, <a href="/A276595/b276595.txt">Table of n, a(n) for n = 1..223</a>
%F A276595 A276592(n)/A276593(n) + A276594(n)/a(n) = A046988(n)/A002432(n).
%F A276595 Zeta(2n) = (-1)^(n-1)*(A276594(n)/a(n))*((2*Pi)^(2n)), according to Euler. - _Terry D. Grant_, Jun 19 2018
%p A276595 seq(denom(sum(1/(2*k)^(2*n),k=1..infinity)/Pi^(2*n)),n=1..24);
%p A276595 seq(denom(bernoulli(2*n)/2/(2*n)!),n=1..24); # _Robert Israel_, Sep 18 2016
%t A276595 Table[Denominator[Zeta[2*n]/(2*Pi)^(2*n)], {n, 1, 30}] (* _Terry D. Grant_, Jun 19 2018 *)
%o A276595 (PARI) a(n) = denominator(bernfrac(2*n)/(2*(2*n)!)); \\ _Michel Marcus_, Jul 05 2018
%Y A276595 Cf. A002432, A046988, A276592, A276593, A276594.
%K A276595 nonn,frac
%O A276595 1,1
%A A276595 _Martin Renner_, Sep 07 2016