A350490 -id:A350490 - cp's OEIS frontend

A350488 Triangle read by rows: T(n,k) is the number of acyclic digraphs on n unlabeled nodes with k arcs and a global source, n >= 1, k = 0..n*(n-1)/2.

1, 0, 1, 0, 0, 2, 1, 0, 0, 0, 4, 6, 5, 1, 0, 0, 0, 0, 9, 25, 47, 46, 27, 9, 1, 0, 0, 0, 0, 0, 20, 95, 297, 582, 783, 738, 501, 235, 75, 14, 1, 0, 0, 0, 0, 0, 0, 48, 337, 1575, 4941, 11295, 19404, 25847, 26966, 22195, 14380, 7280, 2831, 816, 165, 20, 1

Offset: 1

Andrew Howroyd, Jan 01 2022

			Triangle begins:
  [1] 1;
  [2] 0, 1;
  [3] 0, 0, 2, 1;
  [4] 0, 0, 0, 4, 6,  5,  1;
  [5] 0, 0, 0, 0, 9, 25, 47, 46, 27, 9, 1;
  [6] 0, 0, 0, 0, 0, 20, 95, 297, 582, 783, 738, 501, 235, 75, 14, 1;
  ...

Andrew Howroyd, Table of n, a(n) for n = 1..1350 (rows 1..20)

Row sums are A350415.
Column sums are A350490.
Leading diagonal is A000081.
The labeled version is A350487.
Cf. A122078, A350447, A350449, A350491.

\\ See PARI link in A122078 for program code.
{ my(A=A350488rows(7)); for(i=1, #A, print(A[i])) }

A350492 Number of unlabeled acyclic digraphs with n arcs and a global source and sink.

Original entry on oeis.org

1, 1, 1, 2, 5, 14, 44, 153, 584, 2414, 10732, 50909, 256198, 1360645, 7593530, 44366458, 270517289, 1716555943, 11308051214, 77170484915, 544525867544, 3965944595335, 29769162604337, 229970873746105, 1826057472681595, 14886348784740516

Offset: 0

Andrew Howroyd, Jan 08 2022

nonn

Andrew Howroyd, Table of n, a(n) for n = 0..40

Column sums of A350491.

Cf. A122078, A345258, A350451, A350490.

A350492seq(20) \\ See PARI link in A122078 for program code.

cp's OEIS Frontend

A350488 Triangle read by rows: T(n,k) is the number of acyclic digraphs on n unlabeled nodes with k arcs and a global source, n >= 1, k = 0..n*(n-1)/2.

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