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%I #8 Jul 12 2018 02:46:56
%S 1,2,5,11,24,48,95,178,328,585,1025,1754,2958,4897,8002,12889,20523,
%T 32289,50296,77550,118521,179553,269881,402532,596178,876942,1281777,
%U 1862015,2689405,3862891,5519403,7846393,11100970,15632733,21917280
%N Three-quadrant Ferrers graphs that partition n.
%D G. E. Andrews, Three-quadrant Ferrers graphs, Indian J. Math., 42 (No. 1, 2000), 1-7.
%H Vaclav Kotesovec, <a href="/A059776/b059776.txt">Table of n, a(n) for n = 0..10000</a>
%F a(n) ~ exp(Pi*sqrt(2*n)) / (2^(11/2) * n^(3/2)). - _Vaclav Kotesovec_, Jul 12 2018
%p t1 := add( (-1)^(j)*q^(j*(j+1)/2)*(1-q^(j+1))/(1-q),j=0..101); t3 := mul((1-q^n)^3,n=1..101); series(t1/t3,q,101);
%t nmax = 50; CoefficientList[Series[Sum[(-1)^k*x^(k*(k+1)/2)*(1 - x^(k + 1))/(1 - x), {k, 0, nmax}]/Product[(1 - x^k)^3, {k, 1, nmax}], {x, 0, nmax}], x] (* _Vaclav Kotesovec_, Jul 11 2018 *)
%Y Cf. A000041, A001522, A059777.
%K nonn,easy
%O 0,2
%A _N. J. A. Sloane_, Feb 21 2001
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