%I M3636 #20 Oct 27 2023 08:08:43
%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) onward added by _N. J. A. Sloane_, Oct 19 2006 from the Robinson reference