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 A383842 #15 May 12 2025 10:01:49
%S A383842 1,20,230,2000,14627,95060,567240,3174400,16904053,86549620,429352330,
%T A383842 2075659600,9822847079,45665147700,209129160300,945597624000,
%U A383842 4229196800505,18738054705300,82347219011950,359322115058000,1558151553849131,6719660438870420,28838298857544080
%N A383842 Expansion of 1/((1-x) * (1-2*x) * (1-3*x) * (1-4*x))^2.
%H A383842 <a href="/index/Rec#order_08">Index entries for linear recurrences with constant coefficients</a>, signature (20,-170,800,-2273,3980,-4180,2400,-576).
%F A383842 a(n) = 20*a(n-1) - 170*a(n-2) + 800*a(n-3) - 2273*a(n-4) + 3980*a(n-5) - 4180*a(n-6) + 2400*a(n-7) - 576*a(n-8).
%F A383842 a(n) = Sum_{k=0..n} Stirling2(k+4,4) * Stirling2(n-k+4,4).
%o A383842 (PARI) a(n) = sum(k=0, n, stirling(k+4, 4, 2)*stirling(n-k+4, 4, 2));
%Y A383842 Column k=4 of A383843.
%Y A383842 Cf. A000453.
%K A383842 nonn,easy
%O A383842 0,2
%A A383842 _Seiichi Manyama_, May 12 2025