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 A382677 #11 Aug 30 2025 12:22:10 %S A382677 1,13,77,325,1181,3973,12797,40165,124061,379333,1152317,3485605, %T A382677 10514141,31657093,95200637,286060645,859099421,2579133253,7741069757, %U A382677 23230549285,69706327901,209148343813,627503751677,1882628695525,5648120967581,16944832664773 %N A382677 a(n) = 9 - 28 * 2^n + 20 * 3^n. %H A382677 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (6,-11,6). %F A382677 From _Stefano Spezia_, Aug 30 2025: (Start) %F A382677 G.f.: (1 + 2*x)*(1 + 5*x)/((1 - x)*(1 - 2*x)*(1 - 3*x)). %F A382677 E.g.f.: exp(x)*(2*exp(x) - 1)*(10*exp(x) - 9). (End) %o A382677 (PARI) a(n) = 9-28*2^n+20*3^n; %Y A382677 Column k=2 of A382674. %Y A382677 Row n=2 of A382674. %K A382677 nonn,easy,changed %O A382677 0,2 %A A382677 _Seiichi Manyama_, Apr 03 2025