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Search: id:A091478
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| A091478 |
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Table of graphs with n (>=1) nodes and k (>=0) edges. Each type of object labeled from its own label set. |
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+0
3
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| 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; listen)
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OFFSET
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1,5
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REFERENCES
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F. Bergeron, G. Labelle and P. Leroux, Combinatorial Species and Tree-Like Structures, Cambridge, 1998, pg 114 (2.4.44)
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FORMULA
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a(n, k) = k!*binomial(binomial(n, 2), k).
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EXAMPLE
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1; 1,1; 1,3,6,6; 1,6,30,120,360,720,720; Row lengths in A000124(n+1).
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CROSSREFS
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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: A152422 A152139 A021736 this_sequence A086727 A021277 A016662
Adjacent sequences: A091475 A091476 A091477 this_sequence A091479 A091480 A091481
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KEYWORD
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nonn,tabf
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AUTHOR
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Christian G. Bower (bowerc(AT)usa.net), Jan 13 2004
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