A327986 Denominators of the coefficients in the expansion of (4*sinh(sqrt(x)/2)^2*cosh(sqrt(x)))/x.

1, 12, 360, 20160, 259200, 239500800, 43589145600, 1494484992000, 3201186852864000, 1216451004088320000, 11469395181404160000, 310224200866619719680000, 201645730563302817792000000, 21777738900836704321536000000, 132626429906095529318154240000000

Offset: 0

Author

Peter Luschny, Oct 05 2019

Keywords

• nonn
• frac

Examples

			r(n) = 1, 7/12, 31/360, 127/20160, 73/259200, 2047/239500800, 8191/43589145600, ...
		

Crossrefs

Numerators in A327497.

Programs

Maple

gf := (4*sinh(sqrt(x)/2)^2*cosh(sqrt(x)))/x: ser := series(gf, x, 40):
seq(denom(coeff(ser, x, n)), n=0..14);

Formula

a(n) = denominator [x^n] (cosh(2*sqrt(x)) - 2*cosh(sqrt(x)) + 1)/x.