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 A218140 #7 Sep 21 2024 15:04:43
%S A218140 1,9,419,35052,3932898,525079969,78585936821,12747573200724,
%T A218140 2194994259274978,395736626092691782,73998168736285644408,
%U A218140 14252983638239681717320,2813522889710891871593558,566979470344349452319862891,116289126161824019718614903183
%N A218140 Central coefficients of triangle A181144.
%C A218140 The g.f. of triangle A181144 is exp( Sum_{n>=1} [Sum_{k=0..n} C(n,k)^4*y^k] * x^n/n ).
%o A218140 (PARI) {a(n)=polcoeff(polcoeff(exp(sum(m=1, 2*n, sum(j=0, m, binomial(m, j)^4*y^j)*x^m/m)+O(x^(2*n+1))), 2*n, x), n, y)}
%o A218140 for(n=0, 20, print1(a(n), ", "))
%Y A218140 Cf. A181144.
%K A218140 nonn
%O A218140 0,2
%A A218140 _Paul D. Hanna_, Oct 21 2012