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 A250121 #17 Apr 30 2022 11:30:06
%S A250121 1,6,15,30,49,73,102,135,174,217,265,318,375,438,505,577,654,735,822,
%T A250121 913,1009,1110,1215,1326,1441,1561,1686,1815,1950,2089,2233,2382,2535,
%U A250121 2694,2857,3025,3198,3375,3558,3745,3937,4134
%N A250121 Crystal ball sequence for planar net 3.3.3.3.6.
%C A250121 The g.f. was proven; cf. the comment in A250120. - _Georg Fischer_, Jul 19 2020
%H A250121 <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1,0,0,1,-2,1).
%F A250121 G.f.: (x^2+x+1)*(x^4+3*x^3+3*x+1)/((x^4+x^3+x^2+x+1)*(1-x)^3).
%t A250121 CoefficientList[Series[(x^2+x+1)*(x^4+3*x^3+3*x+1)/((x^4+x^3+x^2+x+1)*(1-x)^3),{x,0,41}],x] (* _Georg Fischer_, Jul 19 2020 *)
%t A250121 LinearRecurrence[{2,-1,0,0,1,-2,1},{1,6,15,30,49,73,102},50] (* _Harvey P. Dale_, Apr 30 2022 *)
%Y A250121 Partial sums of A250120.
%K A250121 nonn,easy
%O A250121 0,2
%A A250121 _Bradley Klee_ and _N. J. A. Sloane_, Nov 23 2014