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 A022284 #22 Jul 04 2022 18:33:27
%S A022284 0,13,53,120,214,335,483,658,860,1089,1345,1628,1938,2275,2639,3030,
%T A022284 3448,3893,4365,4864,5390,5943,6523,7130,7764,8425,9113,9828,10570,
%U A022284 11339,12135,12958,13808,14685,15589
%N A022284 a(n) = n*(27*n - 1)/2.
%H A022284 G. C. Greubel, <a href="/A022284/b022284.txt">Table of n, a(n) for n = 0..5000</a>
%H A022284 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (3,-3,1).
%F A022284 a(n) = a(n-1) + 27*n - 14 for n>0, a(0)=0. - _Vincenzo Librandi_, Aug 04 2010
%F A022284 G.f.: x*(13 + 14*x)/(1 - x)^3 . - _R. J. Mathar_, Aug 04 2016
%F A022284 a(n) = A000217(14*n-1) - A000217(13*n-1). - _Bruno Berselli_, Oct 14 2016
%F A022284 E.g.f.: (x/2)*(27*x + 26)*exp(x). - _G. C. Greubel_, Aug 23 2017
%t A022284 Table[n (27 n - 1)/2, {n, 0, 40}] (* _Bruno Berselli_, Oct 14 2016 *)
%t A022284 LinearRecurrence[{3,-3,1},{0,13,53},40] (* _Harvey P. Dale_, Jul 04 2022 *)
%o A022284 (PARI) a(n)=n*(27*n-1)/2 \\ _Charles R Greathouse IV_, Jun 17 2017
%Y A022284 Cf. A000217, A022285.
%Y A022284 Cf. similar sequences listed in A022288.
%K A022284 nonn,easy
%O A022284 0,2
%A A022284 _N. J. A. Sloane_