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Coefficients of the '3rd-order' mock theta function chi(q).
10

%I #26 Aug 12 2023 23:00:13

%S 1,1,1,0,0,0,1,1,0,0,-1,0,1,1,1,-1,0,0,0,1,0,0,-1,0,1,1,1,0,-1,-1,1,1,

%T 0,-1,-1,0,1,2,1,-1,-1,0,1,1,0,-1,-2,0,1,2,1,-1,-1,-1,1,2,1,-1,-2,-1,

%U 2,2,1,-1,-2,-1,1,2,0,-1,-3,0,2,3,2,-2,-2,-1,2,3,0,-2,-3,-1,2,3,2,-3,-3,-1,2,4,1,-2,-4,-1,3,4,2,-2,-4

%N Coefficients of the '3rd-order' mock theta function chi(q).

%D N. J. Fine, Basic Hypergeometric Series and Applications, Amer. Math. Soc., 1988; p. 55, Eq. (26.14).

%D Srinivasa Ramanujan, Collected Papers, Chelsea, New York, 1962, pp. 354-355.

%D Srinivasa Ramanujan, The Lost Notebook and Other Unpublished Papers, Narosa Publishing House, New Delhi, 1988, p. 17.

%H G. C. Greubel, <a href="/A053252/b053252.txt">Table of n, a(n) for n = 0..1000</a>

%H Leila A. Dragonette, <a href="http://dx.doi.org/10.1090/S0002-9947-1952-0049927-8">Some asymptotic formulas for the mock theta series of Ramanujan</a>, Trans. Amer. Math. Soc., 72 (1952) 474-500.

%H John F. R. Duncan, Michael J. Griffin and Ken Ono, <a href="http://arxiv.org/abs/1503.01472">Proof of the Umbral Moonshine Conjecture</a>, arXiv:1503.01472 [math.RT], 2015.

%H George N. Watson, <a href="https://doi.org/10.1112/jlms/s1-11.1.55">The final problem: an account of the mock theta functions</a>, J. London Math. Soc., 11 (1936) 55-80.

%F G.f.: chi(q) = Sum_{n >= 0} q^n^2/((1-q+q^2)*(1-q^2+q^4)*...*(1-q^n+q^(2n))).

%F G.f.: G(0), where G(k) = 1 + q^(k+1) / (1 - q^(k+1)) / G(k+1). - _Joerg Arndt_, Jun 29 2013

%t Series[Sum[q^n^2/Product[1-q^k+q^(2k), {k, 1, n}], {n, 0, 10}], {q, 0, 100}]

%Y Other '3rd-order' mock theta functions are at A000025, A053250, A053251, A053253, A053254, A053255, A261401.

%K sign,easy

%O 0,38

%A _Dean Hickerson_, Dec 19 1999