id:A159081 - OEIS Search Results

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Let d be the largest element of A158611 which divides n, then a(n) is the position of d in A158611.

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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; listen)

	OFFSET	`1,2`
	COMMENT	`Let p be the largest prime factor of n; if p = prime(k) then set a(n) = k + 1. a(n) = A061395(n) + 1.`
	FORMULA	`a(n) = A049084(A006530(n)) + 1. A158611(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)=4-th term of A158611, the extended set of primes.`
	CROSSREFS	`Cf.: A061395, A049084, A006530, A158611.` `Sequence in context: A068962 A036380 A139094 this_sequence A141285 A157893 A054384` `Adjacent sequences: A159078 A159079 A159080 this_sequence A159082 A159083 A159084`
	KEYWORD	`nonn,easy`
	AUTHOR	`Jaroslav Krizek (jaroslav.krizek(AT)atlas.cz), Apr 05 2009`
	EXTENSIONS	`Edited by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Apr 06 2009`

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Last modified November 27 22:38 EST 2009. Contains 167602 sequences.

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