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 A090439 #14 Jun 05 2019 14:00:15
%S A090439 1,5,37,-887,-168919,-21607859,-2799384755,-337767590383,
%T A090439 -11912361112367,21032925955607701,16703816669710968821,
%U A090439 10654267957172226744985,6614425802684094455696377,4120103872599589439389105373
%N A090439 Alternating row sums of array A090438 ((4,2)-Stirling2).
%F A090439 a(n) = Sum_{k=2..2*n} ((-1)^k)*A090438(n, k), n>=1, a(0):= 1.
%F A090439 a(n) = (2*n+2)!*hypergeom([-2*n],[3],1)/2, assuming offset 0. - _Peter Luschny_, Apr 08 2015
%p A090439 # assuming offset 0:
%p A090439 p := (n,x) -> (2*n+2)!*hypergeom([-2*n],[3],x)/2;
%p A090439 seq(simplify(p(n,1)), n=0..11); # _Peter Luschny_, Apr 08 2015
%t A090439 a[n_, k_] := (-1)^k/k! Sum[(-1)^p Binomial[k, p] Product[FactorialPower[p + 2(j-1), 2], {j, 1, n}], {p, 2, k}];
%t A090439 a[n_] := Sum[(-1)^k a[n,k], {k, 2, 2n}];
%t A090439 Array[a,14] (* _Jean-François Alcover_, Jun 05 2019 *)
%K A090439 sign,easy
%O A090439 1,2
%A A090439 _Wolfdieter Lang_, Dec 23 2003