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A057273 Triangle T(n,k) of number of strongly connected digraphs on n labeled nodes and with k arcs, k=0,1,..,n*(n-1). 2
1, 0, 0, 1, 0, 0, 0, 2, 9, 6, 1, 0, 0, 0, 0, 6, 84, 316, 492, 417, 212, 66, 12, 1, 0, 0, 0, 0, 0, 24, 720, 6440, 26875, 65280, 105566, 122580, 106825, 71700, 37540, 15344, 4835, 1140, 190, 20, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,8

LINKS

Table of n, a(n) for n=1..45.

EXAMPLE

[1],[0,0,1],[0,0,0,2,9,6,1],[0,0,0,0,6,84,316,492,417,212,66,12,1],...; Number of strongly connected digraphs on 3 labeled nodes is 18=2+9+6+1.

CROSSREFS

Row sums give A003030. Cf. A057270-A057272, A057274-A057279.

Sequence in context: A213819 A193088 A162916 * A236558 A296004 A108986

Adjacent sequences:  A057270 A057271 A057272 * A057274 A057275 A057276

KEYWORD

easy,nonn,tabf

AUTHOR

Vladeta Jovovic, Goran Kilibarda, Sep 14 2000

STATUS

approved

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Last modified November 19 22:34 EST 2019. Contains 329323 sequences. (Running on oeis4.)