A096939 Number of sets of odd number of even lists, cf. A000262.

0, 2, 6, 36, 260, 1950, 19362, 193256, 2326536, 29272410, 413257790, 6231230412, 101415565836, 1769925341366, 32734873484250, 646218442877520, 13404753632014352, 294656673023216946, 6775966692145553526

Offset

1,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..200

Formula

E.g.f.: exp(x/(1-x^2))*sinh(x^2/(1-x^2)).

Recurrence: (n-2)*a(n) = (2*n-3)*a(n-1) + (n-1)*(2*n^2 - 8*n + 7)*a(n-2) + (n-2)*(n-1)*(2*n-5)*a(n-3) - (n-4)*(n-3)*(n-2)^2*(n-1)*a(n-4). - Vaclav Kotesovec, Sep 29 2013

a(n) ~ exp(2*sqrt(n)-n-1/2)*n^(n-1/4)/(2*sqrt(2)) * (1-5/(48*sqrt(n))). - Vaclav Kotesovec, Sep 29 2013

a(n) = A000262(n) - A096965(n). - Alois P. Heinz, Dec 01 2021

Mathematica

Drop[ Range[0, 20]! CoefficientList[ Series[ Exp[(x/(1 - x^2))] Sinh[x^2/(1 - x^2)], {x, 0, 20}], x], 1] (* Robert G. Wilson v, Aug 19 2004 *)

Crossrefs

Cf. A000262, A088026, A088009, A096965.

Sequence in context: A177373 A109284 A060178 * A351825 A358080 A369091

Adjacent sequences: A096936 A096937 A096938 * A096940 A096941 A096942

Keyword

easy,nonn

Author

Vladeta Jovovic, Aug 18 2004

Extensions

More terms from Robert G. Wilson v, Aug 19 2004

Status

approved