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 A291562 #5 Sep 08 2017 18:44:05
%S A291562 1,-10,8694,-61647300,1734021238950,-136052492985945900,
%T A291562 24163008287867047021500,-8459330090805576230333085000,
%U A291562 5291501479813583484914737466943750,-5495231184920767021604909502973944937500,8949980571079076055152283884403171536694652500,-21844650683271846600479522545258218405196394185875000,76989791585920262367039920605319026539360791969735659537500
%N A291562 Central terms of triangle A291560: a(n) = A291560(2*n-1,n) for n>=1.
%C A291562 The e.g.f. G(x,k) of triangle A291560 satisfies: sin(G(x,k)) = k * sin(x).
%o A291562 (PARI) {A291560(n, r) = (2*n-1)! * polcoeff( polcoeff( asin( k*sin(x + O(x^(2*n)))), 2*n-1, x), 2*r-1, k)}
%o A291562 for(n=1, 15, print1(A291560(2*n-1, n), ", "))
%K A291562 sign
%O A291562 1,2
%A A291562 _Paul D. Hanna_, Sep 08 2017