A032182 "CIJ" (necklace, indistinct, labeled) transform of 2,1,1,1...

2, 5, 23, 156, 1409, 15908, 215529, 3406770, 61542033, 1250700672, 28241802929, 701494286870, 19008349975497, 557990502346020, 17639808964667241, 597481099591875594, 21586547569205365409, 828650020968205107752, 33680822283049282596225

Offset

1,1

Links

Table of n, a(n) for n=1..19.

Christian G. Bower, Transforms (2)

INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 837

Index entries for sequences related to necklaces

Formula

E.g.f.: A(x) = log(1/(2-x-exp(x))). - Sean A. Irvine, May 28 2020

a(n) ~ (n-1)! / (2 - LambertW(exp(2)))^n. - Vaclav Kotesovec, May 29 2020

Crossrefs

Cf. A226571.

Sequence in context: A378335 A358608 A242227 * A165902 A191600 A343020

Adjacent sequences: A032179 A032180 A032181 * A032183 A032184 A032185

Keyword

nonn

Author

Christian G. Bower

Extensions

More terms from Sean A. Irvine, May 28 2020

Status

approved