Search: id:A007649 Results 1-1 of 1 results found. %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, An extension of the exponential formula in enumerative combinatorics %H A007649 N. J. A. Sloane, Transforms %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) Search completed in 0.001 seconds