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 A327986 #9 Oct 05 2019 10:26:54 %S A327986 1,12,360,20160,259200,239500800,43589145600,1494484992000, %T A327986 3201186852864000,1216451004088320000,11469395181404160000, %U A327986 310224200866619719680000,201645730563302817792000000,21777738900836704321536000000,132626429906095529318154240000000 %N A327986 Denominators of the coefficients in the expansion of (4*sinh(sqrt(x)/2)^2*cosh(sqrt(x)))/x. %F A327986 a(n) = denominator [x^n] (cosh(2*sqrt(x)) - 2*cosh(sqrt(x)) + 1)/x. %e A327986 r(n) = 1, 7/12, 31/360, 127/20160, 73/259200, 2047/239500800, 8191/43589145600, ... %p A327986 gf := (4*sinh(sqrt(x)/2)^2*cosh(sqrt(x)))/x: ser := series(gf, x, 40): %p A327986 seq(denom(coeff(ser, x, n)), n=0..14); %Y A327986 Numerators in A327497. %K A327986 nonn,frac %O A327986 0,2 %A A327986 _Peter Luschny_, Oct 05 2019