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 A063241 #16 Aug 22 2019 12:18:12
%S A063241 3,5,7,13,15,17,23,25,27,33,35,37,43,45,47,53,55,57,63,65,67,73,75,77,
%T A063241 83,85,87,93,95,97,103,105,107,113,115,117,123,125,127,133,135,137,
%U A063241 143,145,147,153,155,157,163,165
%N A063241 Dimension of the space of weight 2n cuspidal newforms for Gamma_0(90).
%C A063241 The sequence lists the odd numbers ending with 3, 5 and 7. This follows from Mathar's generating function. - _Bruno Berselli_, Feb 16 2016
%H A063241 William A. Stein, <a href="http://wstein.org/Tables/dimskg0new.gp">Dimensions of the spaces S_k^{new}(Gamma_0(N))</a>
%H A063241 William A. Stein, <a href="http://wstein.org/Tables/">The modular forms database</a>
%H A063241 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,1,-1).
%F A063241 G.f.: 3*x -x^2*(-5-2*x-6*x^2+3*x^3) / ( (1+x+x^2)*(x-1)^2 ). - _R. J. Mathar_, Jul 15 2015
%F A063241 a(n) = 2*n + 4*floor(n/3 - 1/3) + 1. This formula follows from Mathar's generating function. - _Bruno Berselli_, Feb 16 2016
%Y A063241 Cf. A063213.
%K A063241 nonn,easy
%O A063241 1,1
%A A063241 _N. J. A. Sloane_, Jul 10 2001