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
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
B. Baker and R. Shostak, Gossips and Telephones, Discrete Mathematics 2 (1972) 191-193. Math. Rev. 46 # 68.
FORMULA
{1, 2, 4, 8, 12, 16} UNION {n:n >= 20 and 2|n}.
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Jonathan Vos Post, Aug 11 2012
STATUS
approved