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A350491
Triangle read by rows: T(n,k) is the number of acyclic digraphs on n unlabeled nodes with k arcs and a global source and sink, n >= 1, k = 0..n*(n-1)/2.
4
1, 0, 1, 0, 0, 1, 1, 0, 0, 0, 1, 4, 4, 1, 0, 0, 0, 0, 1, 9, 25, 32, 22, 8, 1, 0, 0, 0, 0, 0, 1, 17, 92, 259, 441, 496, 379, 195, 66, 13, 1, 0, 0, 0, 0, 0, 0, 1, 28, 259, 1286, 4026, 8754, 13930, 16686, 15289, 10785, 5842, 2397, 722, 151, 19, 1
OFFSET
1,12
LINKS
Andrew Howroyd, Table of n, a(n) for n = 1..1350 (rows 1..20)
EXAMPLE
Triangle begins:
[1] 1;
[2] 0, 1;
[3] 0, 0, 1, 1;
[4] 0, 0, 0, 1, 4, 4, 1;
[5] 0, 0, 0, 0, 1, 9, 25, 32, 22, 8, 1;
[6] 0, 0, 0, 0, 0, 1, 17, 92, 259, 441, 496, 379, 195, 66, 13, 1;
...
PROG
(PARI) \\ See PARI link in A122078 for program code.
{ my(A=A350491rows(7)); for(i=1, #A, print(A[i])) }
CROSSREFS
Row sums are A345258.
Column sums are A350492.
Sequence in context: A204384 A102412 A372005 * A365957 A365954 A260043
KEYWORD
nonn,tabf
AUTHOR
Andrew Howroyd, Jan 08 2022
STATUS
approved