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A223889
The number of connected components of size > 1 over all simple labeled graphs on n nodes.
0
0, 0, 1, 7, 66, 1078, 33812, 2124864, 269617328, 68809824944, 35197776962400, 36032789666289920, 73789365506598519808, 302234307608870314427904, 2475886847109430725963593728, 40564851077856428731075010538496
OFFSET
0,4
FORMULA
E.g.f.: (A(x) - x - 1)*B(x) where A(x) is the e.g.f. for A001187 and B(x) is the e.g.f. for A006125.
MATHEMATICA
nn=15; g=Sum[2^Binomial[n, 2]x^n/n!, {n, 0, nn}]; Range[0, nn]!CoefficientList[Series[(Log[g]-x)g, {x, 0, nn}], x]
CROSSREFS
Cf. A125207
Sequence in context: A215077 A003286 A244602 * A197744 A052351 A210476
KEYWORD
nonn
AUTHOR
Geoffrey Critzer, Mar 28 2013
STATUS
approved