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 A072048 Number of divisors of the squarefree numbers: tau(A005117(n)). 4
 1, 2, 2, 2, 4, 2, 4, 2, 2, 4, 4, 2, 2, 4, 4, 2, 4, 2, 8, 2, 4, 4, 4, 2, 4, 4, 2, 8, 2, 4, 2, 4, 2, 4, 4, 4, 2, 2, 4, 4, 8, 2, 4, 8, 2, 2, 4, 4, 8, 2, 4, 2, 4, 4, 4, 2, 4, 4, 4, 4, 2, 2, 8, 2, 8, 4, 2, 2, 8, 4, 2, 8, 4, 4, 4, 4, 4, 2, 4, 8, 2, 4, 4, 2, 8, 2, 4, 4, 4, 4, 4, 2, 2, 8, 4, 2 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS a(n) = 2^A072047(n) = 2^A001221(A005117(n)). Also the number of cubefree numbers with the same squarefree kernel as the n-th squarefree number, see A073245. LINKS Reinhard Zumkeller, Table of n, a(n) for n = 1..10000 FORMULA a(n) = A000005(A005117(n)). MAPLE A072048:=n->`if`(numtheory[issqrfree](n) = true, numtheory[tau](n), NULL); seq(A072048(k), k=1..100); # Wesley Ivan Hurt, Oct 13 2013 PROG (Haskell) a072048 = (2 ^) . a072047  -- Reinhard Zumkeller, Dec 13 2015 CROSSREFS Cf. A062822. Cf. A000079, A001221, A005117, A072047. Sequence in context: A079405 A332347 A201353 * A161841 A335901 A152674 Adjacent sequences:  A072045 A072046 A072047 * A072049 A072050 A072051 KEYWORD nonn AUTHOR Reinhard Zumkeller, Jun 09 2002 STATUS approved

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Last modified May 16 14:39 EDT 2021. Contains 343949 sequences. (Running on oeis4.)