A130105 a(n) = (2n)! * B_n, where B_n = n-th Bernoulli number.

1, -1, 4, 0, -1344, 0, 11404800, 0, -697426329600, 0, 184310758195200000, 0, -157043899486325440512000, 0, 355703068713666170585088000000, 0, -1866165170959155879636916764672000000, 0, 20448911361268918178782871919840460800000000, 0

Offset

0,3

Links

Table of n, a(n) for n=0..19.

Formula

a(n) = (2n)! * A027641(n)/A027642(n).

a(n) = (2n)! * Sum_{k=0..n} (1/(k+1))*Sum_{j=0..k} (-1)^j*binomial(k,j)*j^n.

Mathematica

Array[(2#)!*BernoulliB[#]&, 18, 0] (* James C. McMahon, Feb 07 2025 *)

Crossrefs

Cf. A027641, A027642.

Sequence in context: A012688 A216675 A012502 * A013463 A013464 A331582

Adjacent sequences: A130102 A130103 A130104 * A130106 A130107 A130108

Keyword

easy,sign,changed

Author

Paul Barry, May 07 2007

Status

approved