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A070880 Look at all 2^(n-1)-1 nonempty subsets S of {1, 2, ..., n-1}; a(n) gives number of such S with property that it is impossible to partition n into parts from S such that each s in S is used at least once. 2
0, 0, 1, 3, 10, 22, 52, 110, 234, 482, 987, 1997, 4035, 8113, 16288, 32644, 65388, 130886, 261922 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

Needs a b-file

LINKS

Table of n, a(n) for n=1..19.

EXAMPLE

a(4)=3 because there are three different subsets S of {1,2,3} satisfying the condition: {3}, {2,3} & {1,2,3}. For the other subsets S, such as {1,2}, there is a partition of 4 which uses them all (such as 4 = 1+1+2).

CROSSREFS

Cf. A088314, A088528.

Sequence in context: A294414 A299336 A222629 * A321335 A171686 A027164

Adjacent sequences:  A070877 A070878 A070879 * A070881 A070882 A070883

KEYWORD

easy,nonn,more

AUTHOR

Naohiro Nomoto, Nov 16 2003

EXTENSIONS

Edited by N. J. A. Sloane, Sep 09 2017

STATUS

approved

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Last modified January 22 15:57 EST 2019. Contains 319364 sequences. (Running on oeis4.)