Hajnal, András; Milner, E. C.; Szemerédi, E. A cure for the telephone disease. (English) Zbl 0251.05132 Can. Math. Bull. 15, 447-450 (1972). Reviewer: R. Tijdeman Page: −5 −4 −3 −2 −1 ±0 +1 +2 +3 +4 +5 Show Scanned Page Cited in 36 Documents MSC: 05C99 Graph theory 05A05 Permutations, words, matrices Citations:Zbl 0245.05002; Zbl 0226.05001 PDFBibTeX XMLCite \textit{A. Hajnal} et al., Can. Math. Bull. 15, 447--450 (1972; Zbl 0251.05132) Full Text: DOI Online Encyclopedia of Integer Sequences: Gossip Problem: there are n people and each of them knows some item of gossip not known to the others. They communicate by telephone and whenever one person calls another, they tell each other all that they know at that time. How many calls are required before each gossip knows everything?