%I A007649 M0824
%S A007649 1,1,2,3,7,9,20,26,54,74,137,184,356,473,841,1154,2034,2742,
%T A007649 4740,6405,10874,14794,24515,33246,54955,74380,120501,163828,
%U A007649 263144,356621,567330,768854,1212354,1644335,2567636,3478873
%N A007649 Number of set-like molecular species of degree n.
%C A007649 A set-like molecular species is formed from the species of sets, E, through 
               species addition, product and substitution.
%D A007649 G. Labelle and P. Leroux, Identities and enumeration: weighting connected 
               components, Abstracts Amer. Math. Soc., 15 (1994), Meeting #896.
%D A007649 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%H A007649 G. Labelle and P. Leroux, <a href="http://www.combinatorics.org/Volume_3/
               volume3_2.html#R12">An extension of the exponential formula in enumerative 
               combinatorics</a>
%H A007649 N. J. A. Sloane, <a href="transforms.txt">Transforms</a>
%F A007649 Euler Transform of A007650. Define c(n): c(0)=0. c(k)=a(k), k>0. A007650=MOEBIUSi(c)-c. 
               (Christian G. Bower (bowerc(AT)usa.net), Feb 23 2006)
%Y A007649 Cf. A000638, A007650.
%Y A007649 Sequence in context: A075855 A140189 A165803 this_sequence A046152 A057239 
               A024541
%Y A007649 Adjacent sequences: A007646 A007647 A007648 this_sequence A007650 A007651 
               A007652
%K A007649 nonn
%O A007649 0,3
%A A007649 Simon Plouffe (simon.plouffe(AT)gmail.com)