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 A218139 #7 Mar 06 2025 20:07:16
%S A218139 1,5,85,2230,73157,2748240,113026865,4958785285,228333859874,
%T A218139 10915734783342,537683100870537,27139187103865728,1397889420026942941,
%U A218139 73245245888401473591,3894386042722560634412,209696591518450916905784,11416666685883303837337577,627639029564864592680196915
%N A218139 Central coefficients of triangle A181143.
%C A218139 The g.f. of triangle A181143 is exp( Sum_{n>=1} [Sum_{k=0..n} C(n,k)^3*y^k] * x^n/n ).
%o A218139 (PARI) {a(n)=polcoeff(polcoeff(exp(sum(m=1, 2*n, sum(j=0, m, binomial(m, j)^3*y^j)*x^m/m)+O(x^(2*n+1))), 2*n, x), n, y)}
%o A218139 for(n=0, 20, print1(a(n), ", "))
%Y A218139 Cf. A181143.
%K A218139 nonn
%O A218139 0,2
%A A218139 _Paul D. Hanna_, Oct 21 2012