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 A014936 #22 May 24 2025 00:24:27
%S A014936 1,39,1122,28558,680163,15536757,344857924,7495831836,160347899205,
%T A014936 3387224876995,70828953712806,1468712060491434,30241806008351527,
%U A014936 618983574479950353,12604083861223212168,255502116339219984952,5159006146988779835529,103805969587115219182431
%N A014936 a(1)=1, a(n) = n*19^(n-1) + a(n-1).
%H A014936 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (39,-399,361).
%F A014936 G.f.: x/((1 - x)*(1 - 19*x)^2). - _Stefano Spezia_, Mar 11 2020
%F A014936 From _Elmo R. Oliveira_, May 22 2025: (Start)
%F A014936 E.g.f.: exp(x)*(1 + exp(18*x)*(342*x - 1))/324.
%F A014936 a(n) = (19^n*(18*n - 1) + 1)/324.
%F A014936 a(n) = 38*a(n-1) - 361*a(n-2) + 1 for n > 2.
%F A014936 a(n) = 39*a(n-1) - 399*a(n-2) + 361*a(n-3) for n >= 4. (End)
%t A014936 RecurrenceTable[{a[1]==1,a[n]==n*19^(n-1)+a[n-1]},a,{n,20}] (* _Harvey P. Dale_, Oct 01 2012 *)
%o A014936 (PARI) a(n) = (1+19^n*(18*n-1))/324; \\ _Jinyuan Wang_, Mar 11 2020
%o A014936 (PARI) my(x='x+O('x^19)); Vec(-x/((x-1)*(19*x-1)^2)) \\ _Elmo R. Oliveira_, May 22 2025
%K A014936 nonn,easy
%O A014936 1,2
%A A014936 _Olivier Gérard_
%E A014936 More terms from _Elmo R. Oliveira_, May 22 2025