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 A086955 #21 Sep 08 2022 08:45:11
%S A086955 1,6,9,18,25,38,49,66,81,102,121,146,169,198,225,258,289,326,361,402,
%T A086955 441,486,529,578,625,678,729,786,841,902,961,1026,1089,1158,1225,1298,
%U A086955 1369,1446,1521,1602,1681,1766,1849,1938,2025,2118,2209,2306,2401,2502
%N A086955 a(n) = n^2 + 2*n + 2 - (-1)^n.
%H A086955 Vincenzo Librandi, <a href="/A086955/b086955.txt">Table of n, a(n) for n = 0..10000</a>
%H A086955 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (2,0,-2,1).
%F A086955 G.f.: (1 + 4*x - 3*x^2 + 2*x^3)/((1+x)*(1-x)^3).
%F A086955 a(2*n) = (2*n+1)^2 = A016754(n), a(2*n+1) = 4*n^2 + 8*n + 6 = A005899(n+1).
%p A086955 A086955:=n->n^2+2*n+2-(-1)^n; seq(A086955(n), n=0..100); # _Wesley Ivan Hurt_, Nov 30 2013
%t A086955 Table[n^2+2n+2-(-1)^n, {n,0,100}] (* _Wesley Ivan Hurt_, Nov 30 2013 *)
%o A086955 (Magma) [n^2+2*n+2-(-1)^n: n in [0..50]]; // _Vincenzo Librandi_, Sep 06 2011
%Y A086955 Cf. A080335.
%K A086955 nonn,easy
%O A086955 0,2
%A A086955 _Paul Barry_, Jul 25 2003