A098723 a(n) = C(n, 4)^(n-5).

1, 1, 15, 1225, 343000, 252047376, 408410100000, 1291467969000000, 7281760530523359375, 68304345527688750390625, 1009036084126126084036009001, 22455695662847780324059072265625, 725747031014354499889356800000000000, 33031134065402989058412384256000000000000

Offset

4,3

Comments

Comment from Saverio Caminiti and Emanuele G. Fusco (fusco(AT)di.uniroma1.it), Sep 18 2007: 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 4-arch graphs on n nodes. The correct sequence is given in our paper.

Links

Vincenzo Librandi, Table of n, a(n) for n = 4..140

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, 4)^(n-5), n=4..19 );

Mathematica

Table[Binomial[n, 4]^(n-5), {n, 4, 20}] (* Harvey P. Dale, Aug 14 2014 *)

Prog

(Magma) [Binomial(n, 4)^(n-5): n in [4..20]]; // Vincenzo Librandi, Aug 15 2014

Crossrefs

Cf. A098721, A098722, A098724.

Sequence in context: A059383 A206394 A354385 * A120296 A209679 A135810

Adjacent sequences: A098720 A098721 A098722 * A098724 A098725 A098726

Keyword

easy,nonn

Author

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

Extensions

More terms from Harvey P. Dale, Aug 14 2014

Status

approved