A374573 Number of sets of nonempty subsets of [n] where each element appears in at most n subsets.

1, 2, 8, 109, 11087, 15312665, 422059040480, 312210595377427422, 7962423724145466121172404, 8668986293188852191645897272339367

Offset: 0

Author

Alois P. Heinz, Jul 11 2024

Keywords

• nonn
• more

Examples

			a(0) = 1: {}.
a(1) = 2: {}, {{1}}.
a(2) = 8: {}, {{1}}, {{2}}, {{1,2}}, {{1},{2}}, {{1},{1,2}}, {{2},{1,2}}, {{1},{2},{1,2}}.
		

Crossrefs

Main diagonal of A330964.

Formula

a(n) = A330964(n,n).