id:A118541 - OEIS Search Results

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Product of digits of prime factors of n, with multiplicity.

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1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 1, 12, 3, 14, 15, 16, 7, 18, 9, 20, 21, 2, 6, 24, 25, 6, 27, 28, 18, 30, 3, 32, 3, 14, 35, 37, 21, 18, 9, 40, 4, 42, 12, 4, 45, 12, 28, 48, 49, 50, 21, 12, 15, 54, 5, 56, 27, 36, 45, 60, 6, 6, 63, 64, 15, 6, 42, 28, 18, 70, 7, 72, 21, 42, 75, 36, 7, 18 (list; graph; listen)

	OFFSET	`0,3`
	COMMENT	`See also: A007954 Product of digits of n. See also: A118503 Sum of digits of prime factors of n, with multiplicity.`
	FORMULA	`a(n) = Prod[i=1..k] (e_i)A007954(p_i) where prime decomposition of n = (p_1)^(e_1) (p_2)^(e_2) * ... * (p_k)^(e_k).`
	EXAMPLE	`a(22) = 2 because 22 = 2 * 11, and the digital product of 2 * the digital product of 11 = 2 * ! * 1 = 2.` `a(121) = 1 because 121 = 11^2 = 11 * 11, multiplying the digits of the prime factors with multiplicity gives A007954(11) +A007954(11) = 1 * 1 = 1.`
	CROSSREFS	`Cf. A001221, A001222, A007953, A007954, A095402.` `Sequence in context: A010889 A053831 A067453 this_sequence A084905 A137564 A106612` `Adjacent sequences: A118538 A118539 A118540 this_sequence A118542 A118543 A118544`
	KEYWORD	`base,easy,nonn`
	AUTHOR	`Jonathan Vos Post (jvospost3(AT)gmail.com), May 06 2006`

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Last modified November 18 20:14 EST 2008. Contains 147244 sequences.

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