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 A038372 Largest subset of integers [ 1...n ] such that no member divides two others. 0
 1, 2, 2, 3, 4, 4, 5, 6, 6, 7, 8, 8, 9, 10, 10, 11, 12, 12, 13, 14, 14, 15, 16, 16, 17, 18, 19, 20, 21, 21, 22, 22, 22, 23, 24, 24, 25, 26, 26, 27, 28, 28, 29, 30 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 REFERENCES R. K. Guy, Unsolved Problems Number Theory, B24. LINKS FORMULA a(n) >= ceiling(2n/3). For large n, 0.6725n <= a(n) <= 0.6736n (see Guy). EXAMPLE {6,8-17,19-23,25-29} is the largest set of positive integers <= 29 such that none of them divides two of the others. The cardinality of the set is 21, so a(29)=21. CROSSREFS Sequence in context: A195124 A032509 A004523 * A121930 A020909 A075357 Adjacent sequences:  A038369 A038370 A038371 * A038373 A038374 A038375 KEYWORD nonn AUTHOR EXTENSIONS More terms and additional comments from Jud McCranie, Jan 17 2001 STATUS approved

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Last modified May 24 14:50 EDT 2013. Contains 225624 sequences.