A215459 Arises in quick gossiping without duplicate transmission.

1, 2, 4, 8, 12, 16, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98, 100, 102, 104, 106, 108, 110

Offset

1,2

Comments

As explained in Seress, there are n persons each knowing a piece of gossip not known to the others. They communicate by telephone and whenever two persons talk they tell the other all of the gossip they know at that time. a(n) lists those n for which there exists a number of economical calls, that is, the minimum, with the additional constraint that everybody hears each piece of gossip exactly once.

References

B. Baker and R. Shostak, "Gossips and Telephones", Discrete Math, 2(191-193, 1972.

Akos Seress, "Quick Gossiping Without Duplicate Transmission", Proceedings of the Third International Conference on Combinatorial Mathematics, Pages 375 - 382, New York Academy of Sciences New York, NY, 1989.

Links

Table of n, a(n) for n=1..52.

Formula

{1, 2, 4, 8, 12, 16} UNION {n:n >= 20 and 2|n}.

Crossrefs

Sequence in context: A024908 A358308 A325326 * A019442 A048166 A360013

Adjacent sequences: A215456 A215457 A215458 * A215460 A215461 A215462

Keyword

nonn,easy

Author

Jonathan Vos Post, Aug 11 2012

Status

approved