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 A063206 #19 Aug 22 2019 12:18:12
%S A063206 2,7,13,17,23,27,33,37,43,47,53,57,63,67,73,77,83,87,93,97,103,107,
%T A063206 113,117,123,127,133,137,143,147,153,157,163,167,173,177,183,187,193,
%U A063206 197,203,207,213,217,223,227,233,237,243,247
%N A063206 Dimension of the space of weight 2n cuspidal newforms for Gamma_0( 31 ).
%C A063206 The terms obey a(n)=10*(n-1)-a(n-1), n>2 as far as tabulated, [_Vincenzo Librandi_, Dec 07 2010, corrected by _R. J. Mathar_, Dec 07 2010]
%H A063206 William A. Stein, <a href="http://wstein.org/Tables/dimskg0new.gp">Dimensions of the spaces S_k^{new}(Gamma_0(N))</a>
%H A063206 William A. Stein, <a href="http://wstein.org/Tables/">The modular forms database</a>
%H A063206 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (1,1,-1).
%F A063206 From _Colin Barker_, Oct 16 2014: (Start)
%F A063206 a(n) = -5/2-(-1)^n/2+5*n for n>1.
%F A063206 a(n) = a(n-1)+a(n-2)-a(n-3) for n>4.
%F A063206 G.f.: -x*(x^3-4*x^2-5*x-2) / ((x-1)^2*(x+1)).
%F A063206 (End)
%K A063206 nonn
%O A063206 1,1
%A A063206 _N. J. A. Sloane_, Jul 10 2001