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A057274 Triangle T(n,k) of number of digraphs with a source on n labeled nodes with k arcs, k=0,1,..,n*(n-1). 2
1, 0, 2, 1, 0, 0, 9, 20, 15, 6, 1, 0, 0, 0, 64, 330, 720, 914, 792, 495, 220, 66, 12, 1, 0, 0, 0, 0, 625, 5804, 24560, 63940, 117310, 164260, 183716, 167780, 125955, 77520, 38760, 15504, 4845, 1140, 190, 20, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

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

EXAMPLE

[1],[0,2,1],[0,0,9,20,15,6,1],[0,0,0,64,330,720,914,792,495,220,66,12,1],...; Number of digraphs with a source on 3 labeled nodes is 51=9+20+15+6+1.

CROSSREFS

Row sums give A003028. Cf. A057270-A057273, A057275-A057279.

Sequence in context: A057271 A021480 A201299 * A088632 A057272 A062735

Adjacent sequences:  A057271 A057272 A057273 * A057275 A057276 A057277

KEYWORD

nonn,tabf

AUTHOR

Vladeta Jovovic, Goran Kilibarda, Sep 14 2000

STATUS

approved

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Last modified September 19 23:31 EDT 2019. Contains 327207 sequences. (Running on oeis4.)