A362337 a(n) = n! * Sum_{k=0..floor(n/2)} (-k)^k / (k! * (n-2*k)!).

1, 1, -1, -5, 37, 221, -2549, -21041, 342665, 3604537, -75816809, -970017949, 25012223149, 377031935125, -11513789879773, -199833956857289, 7052339905578001, 138505710577529969, -5546345926322582225, -121599560980889072693, 5447342134797972438581

Offset

0,4

Links

Table of n, a(n) for n=0..20.

Eric Weisstein's World of Mathematics, Lambert W-Function.

Formula

E.g.f.: exp(x) / (1 + LambertW(x^2)).

Prog

(PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(exp(x)/(1+lambertw(x^2))))

Crossrefs

Cf. A069856, A362338, A362339.

Cf. A362347.

Sequence in context: A095924 A270019 A179567 * A339386 A088582 A088583

Adjacent sequences: A362334 A362335 A362336 * A362338 A362339 A362340

Keyword

sign

Author

Seiichi Manyama, Apr 17 2023

Status

approved