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A098723 a(n) = C(n, 4)^(n-5). 4
1, 1, 15, 1225, 343000, 252047376, 408410100000, 1291467969000000, 7281760530523359375, 68304345527688750390625, 1009036084126126084036009001, 22455695662847780324059072265625, 725747031014354499889356800000000000, 33031134065402989058412384256000000000000 (list; graph; refs; listen; history; text; internal format)
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: A211901 A059383 A206394 * 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

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Last modified April 5 10:28 EDT 2020. Contains 333239 sequences. (Running on oeis4.)