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 A291450 #10 Jun 15 2019 10:31:20
%S A291450 1,4,140,28,20020,4004,6466460,184756,148728580,29745716,133706993420,
%T A291450 2431036244,449741705140,31885268,670910837521540,134182167504308,
%U A291450 409926521725660940,4822664961478364,1278006214791766460,1921813856829724,242081282475556183660,4401477863191930612
%N A291450 Denominators of Integral_{x=0..1} P(n, x)^3 with P(n, x) = Sum_{k=0..n}(-1)^(n-k)* Stirling2(n, k)*k!*x^k.
%C A291450 See A291449 and A290694 for comments.
%p A291450 # Function BG_row is defined in A290694.
%p A291450 seq(BG_row(3, n, "den", "val"), n=0..20);
%t A291450 P[n_, x_] := Sum[(-1)^(n-k)*StirlingS2[n, k]*k!*x^k, {k, 0, n}];
%t A291450 a[n_] := Integrate[P[n, x]^3, {x, 0, 1}] // Denominator;
%t A291450 Table[a[n], {n, 0, 21}] (* _Jean-François Alcover_, Jun 15 2019 *)
%Y A291450 Cf. A164555/A027642, A212196/A181131, A291449/A291450, A290694/A290695, A291447/A291448.
%K A291450 nonn,frac
%O A291450 0,2
%A A291450 _Peter Luschny_, Aug 24 2017