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A057279 Triangle T(n,k) of number of digraphs with a quasi-source on n unlabeled nodes and with k arcs, k=0,1,..,n*(n-1). 9
1, 0, 1, 1, 0, 0, 3, 4, 4, 1, 1, 0, 0, 0, 7, 21, 37, 47, 38, 27, 13, 5, 1, 1, 0, 0, 0, 0, 18, 90, 309, 661, 1125, 1477, 1665, 1489, 1154, 707, 379, 154, 61, 16, 5, 1, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,7

LINKS

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

V. Jovovic and G. Kilibarda, Enumeration of labeled quasi-initially connected digraphs, Discrete Math., 224 (2000), 151-163.

EXAMPLE

Table starts:

[1],

[0,1,1],

[0,0,3,4,4,1,1],

[0,0,0,7,21,37,47,38,27,13,5,1,1],

...

Number of digraphs with a quasi-source on 3 unlabeled nodes is 13=3+4+4+1+1.

CROSSREFS

Row sums give A049512. Cf. A057270-A057278.

Sequence in context: A021748 A132723 A260180 * A054733 A204255 A283753

Adjacent sequences:  A057276 A057277 A057278 * A057280 A057281 A057282

KEYWORD

more,nonn,tabf

AUTHOR

Vladeta Jovovic, Goran Kilibarda, Sep 14 2000

STATUS

approved

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Last modified December 2 01:44 EST 2021. Contains 349435 sequences. (Running on oeis4.)