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 A383437 #15 Aug 17 2025 02:09:59
%S A383437 1,7,29,153,955,6875,56145,513325,5197415,57749055,698763565,
%T A383437 9147450305,128826591795,1942308614755,31215674165705,532747505761365,
%U A383437 9622751822814655,183398328858349895,3678155373214684005,77434849962414400105,1707438441671237522315
%N A383437 a(1) = 1; a(n) = 5 + n * Sum_{k=1..n-1} a(k).
%F A383437 E.g.f.: -5 - 2*x + (-12*x + 5*exp(x))/(1-x)^2.
%F A383437 a(n) = -12 * n * n! + 5 * Sum_{k=0..n} (k+1)! * binomial(n,k) for n > 1.
%F A383437 a(n) = (n^2 * a(n-1) - 5)/(n-1) for n > 2.
%F A383437 a(n) = (n+2) * a(n-1) - (n-1) * a(n-2) for n > 3.
%o A383437 (PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(-5-2*x+(-12*x+5*exp(x))/(1-x)^2))
%Y A383437 Cf. A007808, A074143, A082425, A082427, A082428, A082430, A383436.
%Y A383437 Cf. A001339.
%K A383437 nonn
%O A383437 1,2
%A A383437 _Seiichi Manyama_, Apr 27 2025