A006989 Log of g.f. of numbers of preferential arrangements.

1, 0, 2, 4, 34, 196, 1826, 17172, 199074, 2510116, 35862562, 559572916, 9577862306, 177417693636, 3546104002338, 75961485384532, 1737273637523362, 42235881659123812, 1087865420946370082, 29589907884231535860, 847576876148087333538, 25501591020532799366404

Offset

0,3

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..200

R. G. Wilson v, Letter to N. J. A. Sloane, Jan. 1993

Formula

E.g.f: log(1 + integral(B)) where B is the e.g.f. for A000670.

Mathematica

CoefficientList[Series[2/((2 - E^x)*(2 + x - Log[2 - E^x])), {x, 0, 20}], x] * Range[0, 20]! (* Vaclav Kotesovec, Feb 24 2014 *)

Prog

(PARI) my(x='x+O('x^33)); Vec(serlaplace(log(1+intformal(1/(2-exp(x)))))) \\ Joerg Arndt, Jan 05 2021

Crossrefs

Cf. A000670.

Sequence in context: A051225 A306582 A103625 * A236399 A132529 A027681

Adjacent sequences: A006986 A006987 A006988 * A006990 A006991 A006992

Keyword

nonn

Author

N. J. A. Sloane

Status

approved