Tijdeman, R. On a telephone problem. (English) Zbl 0226.05001 Nieuw Arch. Wiskd., III. Ser. 19, 188-192 (1971). Page: −5 −4 −3 −2 −1 ±0 +1 +2 +3 +4 +5 Show Scanned Page Cited in 1 ReviewCited in 27 Documents MSC: 05A05 Permutations, words, matrices PDF BibTeX XML Cite \textit{R. Tijdeman}, Nieuw Arch. Wiskd., III. Ser. 19, 188--192 (1971; Zbl 0226.05001) OpenURL 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?