%I A059778
%S A059778 1,0,1,1,1,0,1,1,0,0,1,1,0,0,0,1,1,0,0,0,0,1,1,0,0,0,0,0,1,1,0,
%T A059778 0,0,0,0,0,1,1,0,0,0,0,0,0,0,1,1,0,0,0,0,0,0,0,0,1,1,0,0,0,0,0,
%U A059778 0,0,0,0,1,1,0,0,0,0,0,0,0,0,0,0,1,1,0,0,0,0,0,0,0,0,0,0,0,1,1
%V A059778 1,0,-1,-1,-1,0,1,1,0,0,1,1,0,0,0,-1,-1,0,0,0,0,-1,-1,0,0,0,0,0,1,1,0,
%W A059778 0,0,0,0,0,1,1,0,0,0,0,0,0,0,-1,-1,0,0,0,0,0,0,0,0,-1,-1,0,0,0,0,0,
%X A059778 0,0,0,0,1,1,0,0,0,0,0,0,0,0,0,0,1,1,0,0,0,0,0,0,0,0,0,0,0,-1,-1
%N A059778 Expansion of 1 / product((1+q^(2*n+3))/(1-q^(2*n+2)), n=0..inf).
%C A059778 a(n) = (-1)^n*(t(n)-t(n-1)), n>0, where t(n) = A010054(n) is characteristic 
               function of triangular numbers. - Vladeta Jovovic (vladeta(AT)eunet.rs), 
               Sep 22 2002
%D A059778 G. E. Andrews, Three-quadrant Ferrers graphs, Indian J. Math., 42 (No. 
               1, 2000), 1-7.
%Y A059778 Cf. A059777.
%Y A059778 Sequence in context: A035263 A089045 A070749 this_sequence A104521 A131379 
               A090971
%Y A059778 Adjacent sequences: A059775 A059776 A059777 this_sequence A059779 A059780 
               A059781
%K A059778 sign
%O A059778 0,1
%A A059778 N. J. A. Sloane (njas(AT)research.att.com), Feb 21 2001