A306149 a(n) = denominator(n!*[z^n](z*(exp(z)+2*exp(-(1/2)*z)*cos((1/2)*z* 3^(1/2)))/(1-exp(-z)))).

1, 2, 2, 1, 10, 1, 14, 1, 10, 1, 22, 1, 910, 1, 10, 1, 170, 1, 1330, 1, 110, 1, 230, 1, 910, 1, 2, 1, 290, 1, 4774, 1, 1870, 1, 2, 1, 639730, 1, 10, 1, 4510, 1, 33110, 1, 230, 1, 470, 1, 15470, 1, 374, 1, 5830, 1, 2926, 1, 290, 1, 118, 1, 18928910, 1, 110, 1

Offset

0,2

Links

Table of n, a(n) for n=0..63.

Formula

a(2*n - 3) = 1 for n >= 3.

2 divides a(2*n) for n >= 1.

Maple

gf := z*(exp(z)+2*exp(-(1/2)*z)*cos((1/2)*z*sqrt(3)))/(1-exp(-z));
ser := series(gf, z, 70): seq(denom(n!*coeff(ser, z, n)), n=0..63);

Crossrefs

Cf. A306148 (numerator).

Sequence in context: A295855 A364371 A285068 * A134896 A105620 A182002

Adjacent sequences: A306146 A306147 A306148 * A306150 A306151 A306152

Keyword

nonn,frac

Author

Peter Luschny, Aug 19 2018

Status

approved