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A005216 Number of unlabeled identity interval graphs with n nodes.
(Formerly M3636)

%I M3636

%S 1,0,0,0,0,4,31,199,1313,9158,68336,546697,4682870,42818887,416581477,

%T 4298371842,46896673051,539527125454,6528590200432,82900013695783,

%U 1102289694637302,15317689255215159,222056321177147564,3352587738814695770

%N Number of unlabeled identity interval graphs with n nodes.

%D P. J. Hanlon, personal communication.

%D R. W. Robinson, Numerical implementation of graph counting algorithms, AGRC Grant, Math. Dept., Univ. Newcastle, Australia, 1980.

%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

%H R. W. Robinson, <a href="/A005216/b005216.txt">Table of n, a(n) for n = 1..30</a>

%H Phil Hanlon, <a href="http://dx.doi.org/10.1090/S0002-9947-1982-0662044-8">Counting interval graphs</a>, Trans. Amer. Math. Soc. 272 (1982), no. 2, 383-426.

%K nonn

%O 1,6

%A _N. J. A. Sloane_.

%E a(21) on added by _N. J. A. Sloane_, Oct 19 2006 from the Robinson reference.

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Last modified September 19 11:06 EDT 2019. Contains 327192 sequences. (Running on oeis4.)