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 A368535 #8 Dec 29 2023 08:06:49
%S A368535 0,1,6,31,188,1510,16106,217938,3577624,68952495,1524157870,
%T A368535 37974983321,1052320304212,32089921353308,1067586804710258,
%U A368535 38470738234990580,1492501011869912496,62015249735222969325,2747431806313734355830,129267455591507496073315
%N A368535 a(n) = Sum_{k=1..n} binomial(k+2,3) * n^(n-k).
%F A368535 a(n) = [x^n] x/((1-n*x) * (1-x)^4).
%F A368535 a(n) = n * (6*n^(n+2) - n^5 - 3*n^4 + n^3 + n^2 - 6*n + 2)/(6 * (n-1)^4) for n > 1.
%o A368535 (PARI) a(n) = sum(k=1, n, binomial(k+2, 3)*n^(n-k));
%Y A368535 Cf. A062805, A368534.
%Y A368535 Cf. A002663, A097786, A097788.
%K A368535 nonn,easy
%O A368535 0,3
%A A368535 _Seiichi Manyama_, Dec 29 2023