Search: id:A003091 Results 1-1 of 1 results found. %I A003091 M1870 %S A003091 1,1,1,2,8,45,416,6657,189372,9695869,902597327,154043277297,48535481831642, %T A003091 28400190511772276,31020581422991798557,63530150754287203445810, %U A003091 244912468225468597942626507,1783398168624923337196441201196,24605638395579573858211783276124626 %N A003091 [ 2^{n(n-1)/2} / n! ]. %D A003091 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %D A003091 F. Harary and E. M. Palmer, Graphical Enumeration, Academic Press, NY, 1973, p. 246. %p A003091 A003091:n->floor(2^(n*(n-1)/2)/n!); %Y A003091 Sequence in context: A009345 A084553 A144164 this_sequence A119501 A006664 A141117 %Y A003091 Adjacent sequences: A003088 A003089 A003090 this_sequence A003092 A003093 A003094 %K A003091 nonn,easy %O A003091 1,4 %A A003091 N. J. A. Sloane (njas(AT)research.att.com). Search completed in 0.001 seconds