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Search: id:A036360
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| A036360 |
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Number of labeled connected functional digraphs. |
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+0
1
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| 1, 12, 153, 2272, 39225, 776736, 17398969, 435538944, 12058401393, 366021568000, 12090393761721, 431832459644928, 16585599200808937, 681703972229640192, 29858718555221585625, 1388451967046195347456, 68316647610168842824161
(list; graph; listen)
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OFFSET
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0,2
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REFERENCES
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F. Harary and E. Palmer, Graphical Enumeration, (1973), p. 30.
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FORMULA
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a(n) = (n+1)^2 * A001865(n+1). - Gerald McGarvey (gerald.mcgarvey(AT)comcast.net), Apr 17 2008
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MAPLE
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f := proc(n) local k; add(n!*n^(n-k+1)/(n-k)!, k=1..n); end;
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CROSSREFS
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Sequence in context: A103759 A121195 A004356 this_sequence A120657 A015612 A085260
Adjacent sequences: A036357 A036358 A036359 this_sequence A036361 A036362 A036363
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KEYWORD
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nonn,easy
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AUTHOR
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njas
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