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A222807 Number of subsets A of {0,1,...,n-1} with |A+A| > |A-A|. 8

%I #41 Jun 04 2018 11:39:30

%S 0,0,0,0,0,0,0,0,0,0,0,0,0,0,4,10,30,66,144,314,692,1452,3046,6388,

%T 13298,27274,56164,113672,231892,470984,950178,1912700,3868034,

%U 7772172,15651674,31464544,63154106,126603428,254088618,508541874,1018817124

%N Number of subsets A of {0,1,...,n-1} with |A+A| > |A-A|.

%C Some authors work with subsets of [0..n-1], others with subsets of [1..n].

%C Keywords: sum-dominant sets, MSTD sets.

%C 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.

%H <a href="/A222807/b222807.txt">Table of n, a(n) for n = 1..41</a>

%H Greg Martin and Kevin O'Bryant, <a href="http://arxiv.org/abs/math/0608131">Many sets have more sums than differences</a>, arXiv:math/0608131 [math.NT], 2006.

%H D. Penman and M. Wells, <a href="http://www.emis.de/journals/INTEGERS/papers/n57/n57.Abstract.html">On Sets with More Restricted Sums than Differences</a>, Integers, Vol. 13 (2013), A57.

%F a(n) = Sum_{i=1..n} (n-i+1)*A224893(i).

%e The four examples illustrating a(15)=4 are (cf. A140794):

%e 0 2 3 7 10 11 12 14,

%e 0 2 3 4 7 11 12 14,

%e 0 1 2 5 9 10 12 13 14,

%e 0 1 2 4 5 9 12 13 14.

%Y Cf. A118544, A140794, A222808, A224893.

%K nonn,more

%O 1,15

%A _N. J. A. Sloane_, Mar 10 2013

%E a(28)-a(35) from _James Wilcox_, Jul 22 2013

%E a(36)-a(40) from _Giovanni Resta_, Jul 23 2013

%E a(41) from _James Wilcox_, Jul 24 2013

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Last modified April 16 04:38 EDT 2024. Contains 371696 sequences. (Running on oeis4.)