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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.

+0
2

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; listen)

	OFFSET	`1,3`
	COMMENT	`In sumset notation, number of subsets A of {1,...,n} such that the intersection of A and 2A is nonempty.`
	LINKS	`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: A042243 A041887 A129441 this_sequence A065497 A131727 A073371` `Adjacent sequences: A093968 A093969 A093970 this_sequence A093972 A093973 A093974`
	KEYWORD	`nonn`
	AUTHOR	`T. D. Noe (noe(AT)sspectra.com), Apr 20 2004`

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Last modified November 25 13:47 EST 2009. Contains 167481 sequences.

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