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 A271740 #23 Sep 08 2022 08:46:16
%S A271740 2,3,10,23,42,67,98,135,178,227,282,343,410,483,562,647,738,835,938,
%T A271740 1047,1162,1283,1410,1543,1682,1827,1978,2135,2298,2467,2642,2823,
%U A271740 3010,3203,3402,3607,3818,4035,4258,4487,4722,4963,5210,5463,5722,5987,6258,6535,6818,7107,7402,7703
%N A271740 a(n) = 3*n^2 - 2*n + 2.
%C A271740 3*a(n) - 5 is a square. - _Vincenzo Librandi_, Apr 13 2016
%H A271740 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (3,-3,1).
%F A271740 A271713 = A141631 union A271740.
%F A271740 From _Bruno Berselli_, Apr 13 2016: (Start)
%F A271740 O.g.f.: (3 + x + 2*x^2)/(1 - x)^3.
%F A271740 E.g.f.: (3 + 7*x + 3*x^2)*exp(x). (End)
%F A271740 a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n>2. - _Wesley Ivan Hurt_, Apr 13 2016
%p A271740 A271740:=n->3*n^2 - 2*n + 2: seq(A271740(n), n=0..100); # _Wesley Ivan Hurt_, Apr 13 2016
%t A271740 Table[3 n^2 - 2 n + 2, {n, 0, 50}]
%o A271740 (PARI) a(n) = 3*n^2 - 2*n + 2; \\ _Altug Alkan_, Apr 13 2016
%o A271740 (Magma) [3*n^2 - 2*n + 2: n in [0..50]]; // _Bruno Berselli_, Apr 13 2016
%Y A271740 Cf. A141631, A271713.
%K A271740 nonn,easy
%O A271740 0,1
%A A271740 _Ray Chandler_, Apr 13 2016
%E A271740 Definition changed so sequence starts one term earlier. Some formulas may need adjusting. - _N. J. A. Sloane_, Jun 22 2021