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 A173516 #13 Apr 17 2024 00:23:15 %S A173516 1,7,64,769,11536,207649,4360630,104655121,2825688268,84770648041, %T A173516 2797431385354,100707529872745,3927593665037056,164958933931556353, %U A173516 7423152026920035886,356311297292161722529,18171876161900247848980 %N A173516 a(1)=1, a(n) = 3*n*a(n-1) + 1, n > 1. %C A173516 If s(n) is a sequence defined as s(0) = x, s(n) = 3n*s(n-1)+k then s(n) = 3^n*n!*x + a(n)*k, n > 0. %F A173516 E.g.f.: (exp(x)-1) / (1-3*x). - _Kevin Ryde_, Apr 16 2024 %Y A173516 Cf. A002627, A056541. %K A173516 nonn,easy %O A173516 1,2 %A A173516 _Gary Detlefs_, Feb 20 2010