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 A298027 #22 Oct 09 2020 17:29:32
%S A298027 1,7,13,31,43,73,91,133,157,211,241,307,343,421,463,553,601,703,757,
%T A298027 871,931,1057,1123,1261,1333,1483,1561,1723,1807,1981,2071,2257,2353,
%U A298027 2551,2653,2863,2971,3193,3307,3541,3661,3907,4033,4291,4423,4693,4831,5113,5257,5551,5701,6007,6163,6481
%N A298027 Partial sums of A298026.
%H A298027 Robert Israel, <a href="/A298027/b298027.txt">Table of n, a(n) for n = 0..10000</a>
%H A298027 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (1,2,-2,-1,1).
%F A298027 From _Robert Israel_, Jan 21 2018: (Start)
%F A298027 G.f.: (1+6*x+4*x^2+6*x^3+x^4)/((1+x)^2*(1-x)^3).
%F A298027 a(n) = (4+6*n+9*n^2)/4 if n is even, (7+12*n+9*n^2)/4 if n is odd. (End)
%F A298027 Sequence equals values of 9m^2 + 3m + 1 for m = 0, -1, 1, -2, 2, -3, 3, ... . - _Greg Dresden_, Jul 02 2018
%p A298027 seq((4+6*n+9*n^2+(3+6*n)*(n mod 2))/4, n=0..100); # _Robert Israel_, Jan 21 2018
%t A298027 Sort[Table[9 m^2 + 3 m + 1, {m, -20, 20}]] (* _Greg Dresden_, Jul 02 2018 *)
%t A298027 Accumulate[LinearRecurrence[{0,2,0,-1},{1,6,6,18,12},80]] (* _Harvey P. Dale_, Oct 02 2020 *)
%Y A298027 Cf. A298026.
%K A298027 nonn
%O A298027 0,2
%A A298027 _N. J. A. Sloane_, Jan 21 2018