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A057276 Triangle T(n,k) of number of strongly connected digraphs on n unlabeled nodes and with k arcs, k=0,1,..,n*(n-1). 3
1, 0, 0, 1, 0, 0, 0, 1, 2, 1, 1, 0, 0, 0, 0, 1, 4, 16, 22, 22, 11, 5, 1, 1, 0, 0, 0, 0, 0, 1, 7, 58, 240, 565, 928, 1065, 953, 640, 359, 150, 59, 16, 5, 1, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,9

LINKS

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

EXAMPLE

[1],

[0,0,1],

[0,0,0,1,2,1,1],

[0,0,0,0,1,4,16,22,22,11,5,1,1],

...; Number of strongly connected digraphs on 3 unlabeled nodes is 5=1+2+1+1.

CROSSREFS

Row sums give A035512. Cf. A057270-A057275, A057277-A057279.

Sequence in context: A064663 A025923 A138158 * A259829 A035185 A339659

Adjacent sequences:  A057273 A057274 A057275 * A057277 A057278 A057279

KEYWORD

more,nonn,tabf

AUTHOR

Vladeta Jovovic, Goran Kilibarda, Sep 14 2000

STATUS

approved

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Last modified November 27 15:36 EST 2021. Contains 349394 sequences. (Running on oeis4.)