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 A098722 a(n) = C(n, 3)^(n-4). 3

%I

%S 1,1,10,400,42875,9834496,4182119424,2985984000000,3329565857578125,

%T 5487587353600000000,12802485663117464444416,

%U 40833239547181264169598976,173031575921620011303271484375,951166013805414055936000000000000

%N a(n) = C(n, 3)^(n-4).

%C 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 3-arch graphs on n nodes. The correct sequence is given in our paper.

%H Saverio Caminiti and Emanuele G. Fusco, <a href="http://www.cs.uwaterloo.ca/journals/JIS/VOL10/Caminiti/caminiti.html">On the Number of Labeled k-arch Graphs</a>, Journal of Integer Sequences, Vol 10 (2007), Article 07.7.5.

%H C. Lamathe, <a href="http://www.cs.uwaterloo.ca/journals/JIS/VOL7/Lamathe/lamathe2.html">The number of labeled k-arch graphs</a>, Journal of Integer Sequences, Vol. 7 (2004), Article 04.3.1.

%H B. Leclerc, <a href="https://doi.org/10.4000/msh.2858">Graphes d'arches</a>, Math. Sci. Hum. 157 (2002), 27-48.

%p with(combinat); seq( binomial(n,3)^(n-4), n=3..19 );

%Y Cf. A098721, A098723, A098724.

%K easy,nonn

%O 3,3

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

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Last modified May 24 14:36 EDT 2022. Contains 354037 sequences. (Running on oeis4.)