%I A007456
%S A007456 0,1,3,2,4,3,4,3,5,4,5,4,5,4,5,4,6,5,6,5,6,5,6,5,6,5,6,5,6,5,6,5,7,6,7,
%T A007456 6,7,6,7,6,7,6,7,6,7,6,7,6,7,6,7,6,7,6,7,6,7,6,7,6,7,6,7,6,8,7,8,7,8,7,
%U A007456 8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8
%N A007456 Days required to spread gossip to n people.
%C A007456 On first day, each gossip has his own tidbit. On each successive day, 
               disjoint pairs of gossips may share tidbits (over the phone). After 
               a(n) days, all gossips have all tidbits.
%D A007456 Fan, C. Kenneth, Bjorn Poonen and George Poonen, How to spread rumors 
               fast. Mathematics Magazine 70 (Feb, 1997), pp. 40-42.
%D A007456 D. Shasha, Gossiping Defenders, The Puzzling Adventures of Dr. Ecco, 
               pp. 62-4;156 W. H. Freeman NY 1988.
%H A007456 I. Peterson, <a href="http://www.maa.org/mathland/mathland_3_17.html">
               Spreading Rumors</a>, MathLand, March 17, 1997.
%F A007456 a(1) = 0; a(n) = [ log_2 (n-1) ] + ((n-2) mod 2) + 1 (n >= 2)
%F A007456 G.f.: 1/(1-z)*(sum(k>=0, z^(2^k))+1/(1+z))-1. - Ralf Stephan (ralf(AT)ark.in-berlin.de), 
               Apr 06 2003
%Y A007456 Contribution from Johannes W. Meijer (meijgia(AT)hotmail.com), May 24 
               2009: (Start)
%Y A007456 Cf. A160464 and A043529.
%Y A007456 (End)
%Y A007456 Sequence in context: A025509 A130079 A134559 this_sequence A119707 A052938 
               A140114
%Y A007456 Adjacent sequences: A007453 A007454 A007455 this_sequence A007457 A007458 
               A007459
%K A007456 nonn,nice,easy
%O A007456 1,3
%A A007456 Alex Graesser (AlexG(AT)sni.co.za)
%E A007456 More terms from David W. Wilson (davidwwilson(AT)comcast.net)
%E A007456 Formulae corrected by Johannes W. Meijer (meijgia(AT)hotmail.com), May 
               15 2009