A121921 - OEIS

The OEIS is supported by the many generous donors to the OEIS Foundation.

A121921

A102897(n) - 1.

1

1, 3, 13, 121, 4959, 2771103, 151947502947

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

OFFSET

0,2

COMMENTS

Same as A102897, but counts nonempty set systems.

LINKS

Table of n, a(n) for n=0..6.

CROSSREFS

Sequence in context: A057865 A344210 A260847 * A191955 A241458 A302861

Adjacent sequences: A121918 A121919 A121920 * A121922 A121923 A121924

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Mar 17 2007

STATUS

approved