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 A091478 Table of graphs with n (>=1) nodes and k (>=0) edges. Each type of object labeled from its own label set. 2
 1, 1, 1, 1, 3, 6, 6, 1, 6, 30, 120, 360, 720, 720, 1, 10, 90, 720, 5040, 30240, 151200, 604800, 1814400, 3628800, 3628800, 1, 15, 210, 2730, 32760, 360360, 3603600, 32432400, 259459200, 1816214400, 10897286400, 54486432000, 217945728000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,5 REFERENCES F. Bergeron, G. Labelle and P. Leroux, Combinatorial Species and Tree-Like Structures, Cambridge, 1998, p. 114 (2.4.44). LINKS FORMULA a(n, k) = k!*binomial(binomial(n, 2), k). EXAMPLE 1; 1,1; 1,3,6,6; 1,6,30,120,360,720,720; row lengths in A000124(n+1). CROSSREFS Row sums: A091479. Columns 0-2: A000012, A000217(n-1), A033487(n-2). a(n, A000217(n-1)) = A052295(n-1). Cf. A006125, A008406. Sequence in context: A285628 A319886 A021736 * A239567 A198239 A086727 Adjacent sequences:  A091475 A091476 A091477 * A091479 A091480 A091481 KEYWORD nonn,tabf AUTHOR Christian G. Bower, Jan 13 2004 STATUS approved

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Last modified May 28 10:49 EDT 2020. Contains 334681 sequences. (Running on oeis4.)