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 A383841 #15 May 12 2025 10:01:45
%S A383841 1,12,86,480,2307,10044,40792,157440,584693,2107596,7420218,25634880,
%T A383841 87207559,292924668,973531964,3206704800,10482373305,34042285260,
%U A383841 109930177630,353238247200,1130137576331,3601849005372,11440208166816,36225346150080,114391746903037,360325587293004
%N A383841 Expansion of 1/((1-x) * (1-2*x) * (1-3*x))^2.
%H A383841 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (12,-58,144,-193,132,-36).
%F A383841 a(n) = 12*a(n-1) - 58*a(n-2) + 144*a(n-3) - 193*a(n-4) + 132*a(n-5) - 36*a(n-6).
%F A383841 a(n) = Sum_{k=0..n} Stirling2(k+3,3) * Stirling2(n-k+3,3).
%o A383841 (PARI) a(n) = sum(k=0, n, stirling(k+3, 3, 2)*stirling(n-k+3, 3, 2));
%Y A383841 Column k=3 of A383843.
%Y A383841 Cf. A000392, A045618.
%K A383841 nonn,easy
%O A383841 0,2
%A A383841 _Seiichi Manyama_, May 12 2025