A299951 Coefficients in expansion of (E_4^3/E_6^2)^(1/16).

1, 108, 18792, 8775216, 3375768096, 1535055129576, 691959629136096, 325485731190285792, 154751723387164258560, 74822912718767823810204, 36526619326785857845042608, 17998154668247683887778684176, 8931078840823632559970453020032

Offset: 0

Author

Seiichi Manyama, Feb 22 2018

Keywords

• nonn

Links

• Seiichi Manyama, Table of n, a(n) for n = 0..367

Crossrefs

(E_4^3/E_6^2)^(k/288): A289365 (k=1), A299694 (k=2), A299696 (k=3), A299697 (k=4), A299698 (k=6), A299943 (k=8), A299949 (k=9), A289369 (k=12), A299950 (k=16), this sequence (k=18), A299953 (k=24), A299993 (k=32), A299994 (k=36), A300052 (k=48), A300053 (k=72), A300054 (k=96), A300055 (k=144), A289209 (k=288).

Cf. A004009 (E_4), A013973 (E_6), A299857.

Programs

Mathematica

terms = 13;
E4[x_] = 1 + 240*Sum[k^3*x^k/(1 - x^k), {k, 1, terms}];
E6[x_] = 1 - 504*Sum[k^5*x^k/(1 - x^k), {k, 1, terms}];
(E4[x]^3/E6[x]^2)^(1/16) + O[x]^terms // CoefficientList[#, x]& (* Jean-François Alcover, Feb 28 2018 *)

Formula

Convolution inverse of A299857.

a(n) ~ sqrt(2) * Pi^(3/8) * exp(2*Pi*n) / (3^(1/16) * Gamma(1/8) * sqrt(Gamma(1/4)) * n^(7/8)). - Vaclav Kotesovec, Mar 04 2018

a(n) * A299857(n) ~ -sin(Pi/8) * exp(4*Pi*n) / (8*Pi*n^2). - Vaclav Kotesovec, Mar 04 2018