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A093971 Number of sum-full subsets of {1,...,n}; subsets A such that there is a solution to x+y=z for x,y,z in A. 4
0, 1, 2, 7, 16, 40, 86, 195, 404, 873, 1795, 3727, 7585, 15537, 31368, 63582, 127933, 257746, 517312, 1038993, 2081696, 4173322, 8355792, 16731799, 33484323, 67014365, 134069494, 268234688, 536562699, 1073326281 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

In sumset notation, number of subsets A of {1,...,n} such that the intersection of A and 2A is nonempty.

LINKS

Table of n, a(n) for n=1..30.

Eric Weisstein's World of Mathematics, Sum-Free Set

FORMULA

a(n) = 2^n - A007865(n)

CROSSREFS

Cf. A007865 (number of sum-free subsets of 1..n).

Sequence in context: A293378 A041887 A129441 * A065497 A131727 A320236

Adjacent sequences:  A093968 A093969 A093970 * A093972 A093973 A093974

KEYWORD

nonn

AUTHOR

T. D. Noe, Apr 20 2004

STATUS

approved

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Last modified July 17 16:38 EDT 2019. Contains 325107 sequences. (Running on oeis4.)