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 A063213 #17 Aug 22 2019 12:18:12
%S A063213 1,5,9,11,15,19,21,25,29,31,35,39,41,45,49,51,55,59,61,65,69,71,75,79,
%T A063213 81,85,89,91,95,99,101,105,109,111,115,119,121,125,129,131,135,139,
%U A063213 141,145,149,151,155,159,161,165
%N A063213 Dimension of the space of weight 2n cuspidal newforms for Gamma_0(45).
%C A063213 The sequence lists the odd numbers ending with 1, 5 and 9. This follows from Mathar's generating function. - _Bruno Berselli_, Feb 16 2016
%H A063213 William A. Stein, <a href="http://wstein.org/Tables/dimskg0new.gp">Dimensions of the spaces S_k^{new}(Gamma_0(N))</a>
%H A063213 William A. Stein, <a href="http://wstein.org/Tables/">The modular forms database</a>
%H A063213 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,1,-1).
%F A063213 G.f.: x - x^2*(-5-4*x-2*x^2+x^3) / ( (1+x+x^2)*(x-1)^2 ). - _R. J. Mathar_, Jul 15 2015
%F A063213 a(n) = 4*n - 2*floor(n/3 - 1/3) - 3. This formula follows from Mathar's generating function. - _Bruno Berselli_, Feb 16 2016
%Y A063213 Cf. A063241.
%K A063213 nonn,easy
%O A063213 1,2
%A A063213 _N. J. A. Sloane_, Jul 10 2001