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A350750
Triangle read by rows: T(n,k) is the number of strongly connected oriented graphs on n unlabeled nodes with k arcs, n >= 1, k = 0..n*(n-1)/2.
5
1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 2, 1, 0, 0, 0, 0, 0, 1, 5, 18, 27, 19, 6, 0, 0, 0, 0, 0, 0, 1, 8, 80, 333, 765, 1122, 1049, 622, 217, 35, 0, 0, 0, 0, 0, 0, 0, 1, 12, 221, 1875, 8971, 28449, 63845, 105556, 130935, 122607, 85926, 43868, 15506, 3403, 353
OFFSET
1,13
LINKS
Andrew Howroyd, Table of n, a(n) for n = 1..1350 (rows 1..20)
EXAMPLE
Triangle begins:
[1] 1;
[2] 0, 0;
[3] 0, 0, 0, 1;
[4] 0, 0, 0, 0, 1, 2, 1;
[5] 0, 0, 0, 0, 0, 1, 5, 18, 27, 19, 6;
[6] 0, 0, 0, 0, 0, 0, 1, 8, 80, 333, 765, 1122, 1049, 622, 217, 35;
...
PROG
(PARI) \\ See PARI link in A350489 for program code.
{ my(A=A350750rows(7)); for(n=1, #A, print(A[n])) }
CROSSREFS
Row sums are A350489.
Column sums are A350751.
The labeled version is A350731.
Cf. A057276 (digraphs), A350733, A350734.
Sequence in context: A279593 A017867 A127843 * A154234 A091396 A173677
KEYWORD
nonn,tabf
AUTHOR
Andrew Howroyd, Jan 13 2022
STATUS
approved