A098724 a(n) = C(n, 5)^(n-6).

1, 1, 21, 3136, 2000376, 4032758016, 21047953604832, 246803372284575744, 5848571832825267643383, 258055182353934343170048256, 19860857243854539712080765166683, 2528286565488663166137820705009434624

Offset

5,3

Comments

There is a flaw in the paper by Lamathe that we point out in our contribution. This sequence does not give the number of labeled 5-arch graphs on n nodes. The correct sequence is given in our paper. - Saverio Caminiti and Emanuele G. Fusco (fusco(AT)di.uniroma1.it), Sep 18 2007

Links

Table of n, a(n) for n=5..16.

Saverio Caminiti and Emanuele G. Fusco, On the Number of Labeled k-arch Graphs, Journal of Integer Sequences, Vol 10 (2007), Article 07.7.5.

C. Lamathe, The number of labeled k-arch graphs, Journal of Integer Sequences, Vol. 7 (2004), Article 04.3.1.

B. Leclerc, Graphes d'arches, Math. Sci. Hum. 157 (2002), 27-48.

Maple

with(combinat); seq( binomial(n, 5)^(n-6), n=5..19 );

Crossrefs

Cf. A098721, A098722, A098723

Sequence in context: A222096 A018238 A189447 * A326295 A078395 A340331

Adjacent sequences: A098721 A098722 A098723 * A098725 A098726 A098727

Keyword

easy,nonn

Author

Cedric Lamathe (lamathe(AT)loria.fr), Sep 30 2004

Status

approved