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A159081
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Let d be the largest element of A008578 which divides n, then a(n) is the position of d in A008578.
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0
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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; internal format)
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OFFSET
| 1,2
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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.
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FORMULA
| a(n) = A049084(A006530(n)) + 1. A008578(a(n)) = A006530(n);
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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)=4-th term of A008578, the extended set of primes.
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CROSSREFS
| Cf.: A061395, A049084, A006530, A008578.
Sequence in context: A068962 A036380 A139094 * A141285 A157893 A199474
Adjacent sequences: A159078 A159079 A159080 * A159082 A159083 A159084
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KEYWORD
| nonn,easy
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AUTHOR
| Jaroslav Krizek (jaroslav.krizek(AT)atlas.cz), Apr 05 2009
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EXTENSIONS
| Edited by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Apr 06 2009
Correction for change of offset in A158611 and A008578 in Aug 2009 Jaroslav Krizek (jaroslav.krizek(AT)atlas.cz), Jan 27 2010
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