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 A144208 Number of simple graphs on n labeled nodes, where each maximally connected subgraph consists of a single node or has a unique cycle of length 3; also row sums of A144207. 3
 1, 1, 1, 2, 17, 221, 3261, 54801, 1049235, 22695027, 548904831, 14701691121, 432342705351, 13856514927207, 480891887472585, 17971038945463101, 719613541474095591, 30743125693699501431, 1395902175504288127695 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 LINKS Alois P. Heinz, Table of n, a(n) for n = 0..150 FORMULA a(n) = Sum_{k=0..n} A144207(n,k). a(n) ~ c * n^(n-1), where c = 0.762590842281789937101466... . - Vaclav Kotesovec, Sep 10 2014 EXAMPLE a(3) = 2, because there are 2 simple graphs on 3 labeled nodes, where each maximally connected subgraph consists of a single node or has a unique cycle of length 3: .1.2. .1-2. ..... .|/.. .3... .3... MAPLE T:= proc(n, k) option remember; if k=0 then 1 elif k<0 or n add(T(n, k), k=0..n): seq(a(n), n=0..23); MATHEMATICA T[n_, k_] := T[n, k] = Which[k == 0, 1, k<0 || n

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Last modified September 18 10:30 EDT 2019. Contains 327170 sequences. (Running on oeis4.)