A159081 Let d be the largest element of A008578 which divides n, then a(n) is the position of d in A008578.

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

Offset: 1

Author

Jaroslav Krizek, Apr 05 2009

Keywords

• nonn
• easy

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.

Examples

			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.

Formula

a(n) = A049084(A006530(n)) + 1. A008578(a(n)) = A006530(n);

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