id:A069157 - OEIS Search Results

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Number of positive divisors of n that are divisible by smallest prime that divides n.

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0, 1, 1, 2, 1, 2, 1, 3, 2, 2, 1, 4, 1, 2, 2, 4, 1, 3, 1, 4, 2, 2, 1, 6, 2, 2, 3, 4, 1, 4, 1, 5, 2, 2, 2, 6, 1, 2, 2, 6, 1, 4, 1, 4, 4, 2, 1, 8, 2, 3, 2, 4, 1, 4, 2, 6, 2, 2, 1, 8, 1, 2, 4, 6, 2, 4, 1, 4, 2, 4, 1, 9, 1, 2, 3, 4, 2, 4, 1, 8, 4, 2, 1, 8, 2, 2, 2, 6, 1, 6, 2, 4, 2, 2, 2, 10, 1, 3, 4, 6 (list; graph; listen)

	OFFSET	`1,4`
	LINKS	`Leroy Quet, Home Page (listed in lieu of email address)`
	FORMULA	`d(n) e_n/(e_n + 1), where d(n) is the number of positive divisors of n and e_n is the exponent of the smallest prime to divide n in the prime factorization of n.`
	EXAMPLE	`The divisors of 12 which are themselves divisible by 2 (the smallest prime dividing 12) are 2, 4, 6 and 12. So the 12th term is 4.`
	CROSSREFS	`Sequence in context: A127669 A056692 A039637 this_sequence A076526 A033273 A034836` `Adjacent sequences: A069154 A069155 A069156 this_sequence A069158 A069159 A069160`
	KEYWORD	`nonn`
	AUTHOR	`Leroy Quet, Apr 08 2002`

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

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