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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). 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); CROSSREFS Row sums of triangle A144207. A column of A144212. Cf. A053507, A007318. Sequence in context: A126752 A004029 A114268 * A183711 A058239 A006227 Adjacent sequences:  A144205 A144206 A144207 * A144209 A144210 A144211 KEYWORD nonn AUTHOR Alois P. Heinz, Sep 14 2008 STATUS approved

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