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 A159631 #21 May 03 2025 22:26:25 %S A159631 1,1,1,2,1,1,1,2,2,1,1,2,1,1,1,3,1,2,1,2,1,1,1,2,2,1,2,2,1,1,1,3,1,1, %T A159631 1,4,1,1,1,2,1,1,1,2,2,1,1,3,2,2,1,2,1,2,1,2,1,1,1,2,1,1,2,4,1,1,1,2, %U A159631 1,1,1,4,1,1,2,2,1,1,1,3,3,1,1,2,1,1,1,2,1,2,1,2,1,1,1,3,1,2,2,4,1,1,1,2,1,1,1,4,1,1,1,3,1,1,1,2,2,1,1,2,2,1,1,2,3 %N A159631 Dimension of space of modular forms of weight 1/2, level 4*n and trivial character. %C A159631 We have a(n) = A046951(n) for all n < 125, but a(125)=3 > 2=A046951(125). %C A159631 Also, the first nonzero cusp form of weight 1/2 occurs at level 1728. %H A159631 Antti Karttunen, <a href="/A159631/b159631.txt">Table of n, a(n) for n = 1..1200</a> %H A159631 H. Cohen and J. Oesterle, <a href="http://dx.doi.org/10.1007/BFb0065297">Dimensions des espaces de formes modulaires</a>, Modular Functions of One Variable. VI, Proc. 1976 Bonn conf., Lect. Notes in Math. 627, Springer-Verlag, 1977, pp. 69-78. %H A159631 <a href="http://magma.maths.usyd.edu.au/calc/">MAGMA Calculator</a>. %o A159631 (Magma) [[4*n,Dimension(HalfIntegralWeightForms(4*n,1/2))] : n in [1..125]]; %o A159631 (Magma) function a(n) return Dimension( ModularForms( Gamma0(4*n), 1/2)); end function; /* _Michael Somos_, Jun 13 2014 */ %Y A159631 Cf. A046951. %K A159631 nonn %O A159631 1,4 %A A159631 _Steven Finch_, Apr 17 2009 %E A159631 Data section filled up to 125 terms by _Antti Karttunen_, Jul 23 2017