A350910 - OEIS

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A350910

Triangle read by rows: T(n,k) is the number of k-regular digraphs on n unlabeled nodes, k = 0..n-1.

1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1, 2, 5, 2, 1, 1, 4, 23, 23, 4, 1, 1, 4, 92, 415, 92, 4, 1, 1, 7, 624, 19041, 19041, 624, 7, 1, 1, 8, 5021, 1104045, 6510087, 1104045, 5021, 8, 1, 1, 12, 47034, 79818336, 2983458766, 2983458766, 79818336, 47034, 12, 1

(list; table; graph; refs; listen; history; text; internal format)

OFFSET

1,8

LINKS

Table of n, a(n) for n=1..55.

EXAMPLE

Triangle begins:

1, 1;

1, 1, 1;

1, 2, 2, 1;

1, 2, 5, 2, 1;

1, 4, 23, 23, 4, 1;