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A036360 Number of labeled connected functional digraphs. 0
1, 12, 153, 2272, 39225, 776736, 17398969, 435538944, 12058401393, 366021568000, 12090393761721, 431832459644928, 16585599200808937, 681703972229640192, 29858718555221585625, 1388451967046195347456, 68316647610168842824161 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

REFERENCES

F. Harary and E. Palmer, Graphical Enumeration, (1973), p. 30.

LINKS

Table of n, a(n) for n=0..16.

FORMULA

a(n) = (n+1)^2 * A001865(n+1). - Gerald McGarvey, Apr 17 2008

MAPLE

f := proc(n) local k; add(n!*n^(n-k+1)/(n-k)!, k=1..n); end;

CROSSREFS

Sequence in context: A189490 A180808 A004356 * A120657 A015612 A085260

Adjacent sequences:  A036357 A036358 A036359 * A036361 A036362 A036363

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified November 20 14:28 EST 2018. Contains 317402 sequences. (Running on oeis4.)