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 A075592 Numbers n such that number of distinct prime divisors of n is a divisor of n. 13
 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 16, 17, 18, 19, 20, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 34, 36, 37, 38, 40, 41, 42, 43, 44, 46, 47, 48, 49, 50, 52, 53, 54, 56, 58, 59, 60, 61, 62, 64, 66, 67, 68, 71, 72, 73, 74, 76, 78, 79, 80, 81, 82, 83, 84, 86, 88, 89, 90 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Numbers n such that omega(n) divides n. The asymptotic density of this sequence is 0 (Cooper and Kennedy, 1989). - Amiram Eldar, Jul 10 2020 LINKS Christian N. K. Anderson, Table of n, a(n) for n = 1..10000 Curtis N. Cooper, Robert E. Kennedy, Chebyshev's inequality and natural density, Amer. Math. Monthly 96 (1989), no. 2, 118-124. MATHEMATICA Select[Range[2, 100], Divisible[#, Length[Select[Divisors[#], PrimeQ]]]&] (* Harvey P. Dale, Mar 17 2011 *) PROG (R) library(gmp); omega<-function(x) length(unique(as.numeric(factorize(x)))) which(c(F, vapply(2:100, function(n) isint(n/omega(n)), T))) # Christian N. K. Anderson, Apr 25 2013 (PARI) isok(n) = iferr(!(n % omega(n)), E, 0); \\ Michel Marcus, Oct 06 2017 CROSSREFS Different from A070776: 78 belongs to this sequence but not to A070776. Cf. A185307 (complement), A001221, A001222, A074946 (BigOmega(n) divides n). Sequence in context: A317294 A095736 A004829 * A285801 A324109 A070776 Adjacent sequences: A075589 A075590 A075591 * A075593 A075594 A075595 KEYWORD easy,nonn AUTHOR Amarnath Murthy, Sep 26 2002 EXTENSIONS More terms from David Wasserman, Jan 20 2005 "Distinct" added to name by Christian N. K. Anderson, Apr 23 2013 STATUS approved

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Last modified February 21 09:29 EST 2024. Contains 370228 sequences. (Running on oeis4.)