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 A081912 #12 Sep 08 2022 08:45:09 %S A081912 1,6,37,234,1512,9936,66096,443232,2985984,20155392,136048896, %T A081912 917070336,6167549952,41358864384,276451356672,1841557856256, %U A081912 12224809598976,80871817347072,533189772509184,3503818505060352,22952550207062016 %N A081912 a(n) = 6^n*(n^2 - n + 72)/72. %C A081912 Binomial transform of A081911 6th binomial transform of (1,0,1,0,0,0,...). Case k=6 where a(n,k) = k^n*(n^2 - n + 2k^2)/(2k^2) with g.f. (1 - 2kx + (k^2+1)x^2)/(1-kx)^3. %H A081912 Vincenzo Librandi, <a href="/A081912/b081912.txt">Table of n, a(n) for n = 0..150</a> %H A081912 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (18,-108,216). %F A081912 a(n) = 6^n*(n^2 - n + 72)/72. %F A081912 G.f.: (1 - 12x + 37x^2)/(1-6x)^3. %o A081912 (Magma) [6^n*(n^2-n+72)/72: n in [0..40]]; // _Vincenzo Librandi_, Apr 27 2011 %K A081912 easy,nonn %O A081912 0,2 %A A081912 _Paul Barry_, Mar 31 2003