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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: A262147 A057865 A260847 * A191955 A241458 A302861

Adjacent sequences:  A121918 A121919 A121920 * A121922 A121923 A121924

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Mar 17 2007

STATUS

approved

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Last modified April 22 08:56 EDT 2019. Contains 322329 sequences. (Running on oeis4.)