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 A130188 #5 Jul 11 2018 06:39:21
%S A130188 1,4,4,32,16,64,64,1024,256,1024,1024,8192,4096,16384,16384,524288,
%T A130188 65536,262144,262144,2097152,1048576,4194304,4194304,67108864,
%U A130188 16777216,67108864,67108864,536870912,268435456,1073741824
%N A130188 Denominators of rationals r(n) related to the z-sequence of the Sheffer matrix A060821 for Hermite polynomials.
%C A130188 Numerators are A130187.
%C A130188 See A130187 for details on r(n):= A130187(n)/a(n) and the corresponding z-sequence for the Hermite matrix A060821.
%H A130188 G. C. Greubel, <a href="/A130188/b130188.txt">Table of n, a(n) for n = 0..1000</a>
%F A130188 a(n) = denominator(-2*z(2*n+1)), n>=0, with the e.g.f. for z(n) given in A130187.
%t A130188 F:= CoefficientList[Series[-2*(Exp[x^2/4] -1)/x, {x,0,75}], x]*Range[0, 75]!; Table[Denominator[-2*F[[2*n]]], {n, 1, 50}] (* _G. C. Greubel_, Jul 10 2018 *)
%K A130188 nonn,frac,easy
%O A130188 0,2
%A A130188 _Wolfdieter Lang_ Jun 01 2007