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 A159081 Let d be the largest element of A008578 which divides n, then a(n) is the position of d in A008578. 0
 1, 2, 3, 2, 4, 3, 5, 2, 3, 4, 6, 3, 7, 5, 4, 2, 8, 3, 9, 4, 5, 6, 10, 3, 4, 7, 3, 5, 11, 4, 12, 2, 6, 8, 5, 3, 13, 9, 7, 4, 14, 5, 15, 6, 4, 10, 16, 3, 5, 4, 8, 7, 17, 3, 6, 5, 9, 11, 18, 4, 19, 12, 5, 2, 7, 6, 20, 8, 10, 5, 21, 3, 22, 13, 4, 9, 6, 7, 23, 4, 3, 14, 24, 5, 8, 15, 11, 6, 25, 4, 7, 10, 12 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Let p be the largest prime factor of n; if p = prime(k) then set a(n) = k + 1. a(n) = A061395(n) + 1. LINKS FORMULA a(n) = A049084(A006530(n)) + 1. A008578(a(n)) = A006530(n); EXAMPLE For n=30, the largest element of the set {1,2,3,5} (1 and prime divisors of 30) is 5, and 5 is a(n)=4th term of A008578, the extended set of primes. CROSSREFS Cf.: A061395, A049084, A006530, A008578. Sequence in context: A241054 A257907 A139094 * A141285 A286531 A317765 Adjacent sequences:  A159078 A159079 A159080 * A159082 A159083 A159084 KEYWORD nonn,easy AUTHOR Jaroslav Krizek, Apr 05 2009 EXTENSIONS Edited by R. J. Mathar, Apr 06 2009 Correction for change of offset in A158611 and A008578 in Aug 2009 Jaroslav Krizek, Jan 27 2010 STATUS approved

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Last modified May 24 17:09 EDT 2019. Contains 323533 sequences. (Running on oeis4.)