A362894 Triangle read by rows: T(n,k) is the number of simple connected graphs on n unlabeled nodes having Hadwiger number k, 1 <= k <= n.

1, 0, 1, 0, 1, 1, 0, 2, 3, 1, 0, 3, 12, 5, 1, 0, 6, 50, 47, 8, 1, 0, 11, 230, 448, 152, 11, 1

Offset

1,8

Links

Table of n, a(n) for n=1..28.

Eric Weisstein's World of Mathematics, Hadwiger Number

Wikipedia, Hadwiger number

Example

Triangle begins:
1;
0,  1;
0,  1,   1;
0,  2,   3,   1;
0,  3,  12,   5,   1;
0,  6,  50,  47,   8,  1;
0, 11, 230, 448, 152, 11, 1;

Crossrefs

Row sums are A001349.

Cf. A084269.

Cf. A032766 (n-cocktail party graph). A353212 (n-path complement graph).

Sequence in context: A137396 A244213 A346415 * A352067 A368486 A178245

Adjacent sequences: A362891 A362892 A362893 * A362895 A362896 A362897

Keyword

nonn,tabl,hard,more

Author

Peter Kagey, May 08 2023

Status

approved