A118544 Number of subsets A of {1,2,...,n} with |A+A| = |A-A|.

2, 4, 8, 14, 24, 40, 66, 106, 174, 286, 480, 814, 1412, 2480, 4476, 8184, 15230, 28652, 54488, 104262, 201266, 390090, 760234, 1486030, 2914492, 5728506, 11289420, 22279222, 44046072, 87181188, 172777354, 342724456, 680524908, 1352154964, 2688763324

Offset

1,1

Comments

Keywords: sum-dominant sets, MSTD sets.

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

Links

James Wilcox and Giovanni Resta, Table of n, a(n) for n = 1..40 (first 35 terms from James Wilcox)

Example

a(4)=14: two of the sixteen subsets of {1,2,3,4} have |A+A|<|A-A| (specifically, {1,3,4} and {1,2,4}).

Crossrefs

Cf. A222807, A222808, A140794.

Sequence in context: A123655 A084683 A271493 * A222037 A019274 A164173

Adjacent sequences: A118541 A118542 A118543 * A118545 A118546 A118547

Keyword

nonn

Author

Kevin O'Bryant, May 07 2006

Extensions

a(21)-a(29) from Robert Gerbicz, Nov 19 2010

a(30)-a(35) from James Wilcox, Jul 22 2013

Status

approved