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 A222807 Number of subsets A of {0,1,...,n-1} with |A+A| > |A-A|. 8
 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 10, 30, 66, 144, 314, 692, 1452, 3046, 6388, 13298, 27274, 56164, 113672, 231892, 470984, 950178, 1912700, 3868034, 7772172, 15651674, 31464544, 63154106, 126603428, 254088618, 508541874, 1018817124 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,15 COMMENTS Some authors work with subsets of [0..n-1], others with subsets of [1..n]. Keywords: sum-dominant sets, MSTD sets. a(1)-a(21) were computed by Daniel C. R. Scheinerman, Mar 10 2013; although a(1)-a(27) had been found by Kevin O'Bryant some time earlier. LINKS Table of n, a(n) for n = 1..41 Greg Martin and Kevin O'Bryant, Many sets have more sums than differences, arXiv:math/0608131 [math.NT], 2006. D. Penman and M. Wells, On Sets with More Restricted Sums than Differences, Integers, Vol. 13 (2013), A57. FORMULA a(n) = Sum_{i=1..n} (n-i+1)*A224893(i). EXAMPLE The four examples illustrating a(15)=4 are (cf. A140794): 0 2 3 7 10 11 12 14, 0 2 3 4 7 11 12 14, 0 1 2 5 9 10 12 13 14, 0 1 2 4 5 9 12 13 14. CROSSREFS Cf. A118544, A140794, A222808, A224893. Sequence in context: A048044 A047188 A002220 * A090578 A007713 A058488 Adjacent sequences: A222804 A222805 A222806 * A222808 A222809 A222810 KEYWORD nonn,more AUTHOR N. J. A. Sloane, Mar 10 2013 EXTENSIONS a(28)-a(35) from James Wilcox, Jul 22 2013 a(36)-a(40) from Giovanni Resta, Jul 23 2013 a(41) from James Wilcox, Jul 24 2013 STATUS approved

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Last modified April 18 04:56 EDT 2024. Contains 371767 sequences. (Running on oeis4.)