The OEIS is supported by the many generous donors to the OEIS Foundation.
Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.
Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.
%I #5 Nov 03 2017 18:59:30
%S 1,-1,0,1,-1,0,0,0,1,-2,2,0,-3,4,-3,1,1,-4,9,-10,2,11,-19,16,-7,-5,22,
%T -40,43,-13,-42,86,-87,44,24,-106,183,-195,74,163,-382,430,-256,-86,
%U 504,-859,907,-395,-639,1697,-2084,1399,236,-2313,4037,-4301,2080,2529,-7561,9923,-7327
%N Expansion of 1/(Sum_{i>=0} q^(i^2)/Product_{j=1..i} (1 - q^j + q^(2*j))).
%C Convolution inverse of the 3rd order mock theta function chi(q) (A053252).
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/MockThetaFunction.html">Mock Theta Function</a>
%F G.f.: 1/(Sum_{i>=0} q^(i^2)/Product_{j=1..i} (1 - q^j + q^(2*j))).
%t nmax = 60; CoefficientList[Series[1/Sum[q^(i^2)/Product[1 - q^j + q^(2 j), {j, 1, i}], {i, 0, nmax}], {q, 0, nmax}], q]
%Y Cf. A053252, A294407, A294408, A294599, A294600.
%K sign
%O 0,10
%A _Ilya Gutkovskiy_, Nov 03 2017