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 A247155 #16 Nov 29 2024 19:50:45
%S A247155 1,32,125,280,497,776,1117,1520,1985,2512,3101,3752,4465,5240,6077,
%T A247155 6976,7937,8960,10045,11192,12401,13672,15005,16400,17857,19376,20957,
%U A247155 22600,24305,26072,27901,29792,31745,33760,35837,37976,40177,42440,44765,47152,49601
%N A247155 a(n) = 31*n^2 + 1.
%H A247155 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (3,-3,1).
%F A247155 a(0)=1, a(1)=32, a(2)=125, a(3)=280, a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3). - _Harvey P. Dale_, Apr 28 2016
%F A247155 From _Elmo R. Oliveira_, Nov 29 2024: (Start)
%F A247155 G.f.: (32*x^2+29*x+1)/(1-x)^3.
%F A247155 E.g.f.: exp(x)*(1 + 31*x + 31*x^2).
%F A247155 a(n) = A010020(n) - 1 for n>=1. (End)
%t A247155 31*Range[100]^2+1 (* or *) LinearRecurrence[{3,-3,1},{32,125,280},100] (* _Harvey P. Dale_, Apr 28 2016 *)
%o A247155 (PARI) a(n)=31*n^2+1 \\ _Charles R Greathouse IV_, Jun 17 2017
%Y A247155 Cf. A010020.
%K A247155 nonn,easy
%O A247155 0,2
%A A247155 _Garrett Backer_, Nov 21 2014