A234596 Bicolored noncrossing configurations.

1, 8, 80, 992, 13760, 204416, 3180800, 51176960, 844467200, 14212646912, 243034542080, 4210466545664, 73745071063040, 1303643374125056, 23229596506849280, 416799595720736768, 7523942192296755200, 136549608206371389440, 2490043714311736524800, 45601540046865462984704

Offset

1,2

Links

Table of n, a(n) for n=1..20.

F. Chapoton, S. Giraudo, Enveloping operads and bicoloured noncrossing configurations, arXiv preprint arXiv:1310.4521 [math.CO], 2013. See Prop. 2.9.

Samuele Giraudo, Combalgebraic structures on decorated cliques, Formal Power Series and Algebraic Combinatorics, Séminaire Lotharingien de Combinatoire, 78B.15, 2017, p. 8; arXiv:1709.08416 [math.CO], 2017.

Formula

For a g.f. see F. Chapoton, S. Giraudo (2013), Prop. 2.9.

G.f.: 1/6*(1-4*t-sqrt(1-20*t+4*t^2)). - Paul Laubie, Nov 08 2023

Prog

(Sage) R.<t>=PowerSeriesRing(QQ); (1/6*(1-4*t-sqrt(1-20*t+4*t^2))).list()[1:]

Crossrefs

Sequence in context: A053175 A051580 A228658 * A060375 A097815 A002718

Adjacent sequences: A234593 A234594 A234595 * A234597 A234598 A234599

Keyword

nonn

Author

N. J. A. Sloane, Jan 04 2014

Extensions

More terms from Paul Laubie, Nov 08 2023

Status

approved