A293590 E.g.f.: exp(x^3/(1 + x + x^2 + x^3)).

1, 0, 0, 6, -24, 0, 360, 0, -20160, 60480, 1814400, -19958400, -59875200, 2075673600, 21794572800, -860885625600, 3487131648000, 148203095040000, -524638956441600, -71973351075225600, 942749528168448000, 19878836825143296000, -437111394135736320000

Offset

0,4

Links

Table of n, a(n) for n=0..22.

Formula

E.g.f.: Product_{k>0} exp(x^(4*k-1)) / exp(x^(4*k)).

Mathematica

CoefficientList[Series[E^(x^3/(1 + x + x^2 + x^3)), {x, 0, 20}], x] * Range[0, 20]! (* Vaclav Kotesovec, Oct 13 2017 *)

Prog

(PARI) N=66; x='x+O('x^N); Vec(serlaplace(exp(x^3/(1+x+x^2+x^3))))
(PARI) N=66; x='x+O('x^N); Vec(serlaplace(prod(k=1, N, exp(x^(4*k-1)-x^(4*k)))))

Crossrefs

Cf. A111884, A293589.

Sequence in context: A255305 A339628 A304271 * A194770 A052697 A293256

Adjacent sequences: A293587 A293588 A293589 * A293591 A293592 A293593

Keyword

sign

Author

Seiichi Manyama, Oct 12 2017

Status

approved