OFFSET
1,6
COMMENTS
The sum of the in-degree and out-degree at each node is k.
a(2*n,2*n-2) is the number of orientations (up to isomorphism) of the n-cocktail party graph. - Pontus von Brömssen, Apr 03 2022
LINKS
Andrew Howroyd, Table of n, a(n) for n = 1..253 (rows 1..22)
EXAMPLE
Triangle begins:
1;
1, 1;
1, 0, 2;
1, 1, 4, 4;
1, 0, 4, 0, 12;
1, 1, 12, 62, 112, 56;
1, 0, 18, 0, 1602, 0, 456;
...
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Andrew Howroyd, Jan 29 2022
STATUS
approved