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 A053265 #21 Feb 02 2021 21:58:24
%S A053265 1,1,1,1,2,2,2,3,3,3,4,4,5,6,6,7,8,9,10,11,12,13,15,16,18,20,21,24,26,
%T A053265 28,31,34,37,40,44,47,51,56,60,65,71,76,82,89,95,103,111,119,128,138,
%U A053265 148,158,171,182,195,210,223,239,256,273,292,312,332,354,378,402,428
%N A053265 Coefficients of the '5th-order' mock theta function F_1(q).
%D A053265 Srinivasa Ramanujan, Collected Papers, Chelsea, New York, 1962, pp. 354-355.
%D A053265 Srinivasa Ramanujan, The Lost Notebook and Other Unpublished Papers, Narosa Publishing House, New Delhi, 1988, pp. 20, 22, 25.
%H A053265 Vaclav Kotesovec, <a href="/A053265/b053265.txt">Table of n, a(n) for n = 0..10000</a> (terms 0..1000 from Seiichi Manyama)
%H A053265 George E. Andrews, <a href="http://dx.doi.org/10.1090/S0002-9947-1986-0814916-2">The fifth and seventh order mock theta functions</a>, Trans. Amer. Math. Soc., 293 (1986) 113-134.
%H A053265 George E. Andrews and Frank G. Garvan, <a href="http://dx.doi.org/10.1016/0001-8708(89)90070-4">Ramanujan's "lost" notebook VI: The mock theta conjectures</a>, Advances in Mathematics, 73 (1989) 242-255.
%H A053265 George N. Watson, <a href="http://plms.oxfordjournals.org/content/s2-42/1/274.extract">The mock theta functions (2)</a>, Proc. London Math. Soc., series 2, 42 (1937) 274-304.
%F A053265 G.f.: F_1(q) = Sum_{n>=0} q^(2n(n+1))/((1-q)(1-q^3)...(1-q^(2n+1))).
%F A053265 a(n) ~ sqrt(phi) * exp(Pi*sqrt(2*n/15)) / (2^(3/2)*5^(1/4)*sqrt(n)), where phi = A001622 = (1+sqrt(5))/2 is the golden ratio. - _Vaclav Kotesovec_, Jun 12 2019
%t A053265 Series[Sum[q^(2n(n+1))/Product[1-q^(2k+1), {k, 0, n}], {n, 0, 6}], {q, 0, 100}]
%t A053265 nmax = 100; CoefficientList[Series[Sum[x^(2*k*(k+1)) / Product[1-x^(2*j+1), {j, 0, k}], {k, 0, Floor[Sqrt[nmax/2]]}], {x, 0, nmax}], x] (* _Vaclav Kotesovec_, Jun 12 2019 *)
%Y A053265 Other '5th-order' mock theta functions are at A053256, A053257, A053258, A053259, A053260, A053261, A053262, A053263, A053264, A053266, A053267.
%K A053265 nonn,easy
%O A053265 0,5
%A A053265 _Dean Hickerson_, Dec 19 1999