id:A122376 - OEIS Search Results

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Number of prime factors (counted with multiplicity) of the smallest number with exactly n divisors.

+0
6

0, 1, 2, 2, 4, 3, 6, 4, 4, 5, 10, 4, 12, 7, 6, 5, 16, 5, 18, 6, 8, 11, 22, 6, 8, 13, 6, 8, 28, 7, 30, 6, 12, 17, 10, 6, 36, 19, 14, 7, 40, 9, 42, 12, 8, 23, 46, 7, 12, 9, 18, 14, 52, 7, 14, 9, 20, 29, 58, 8, 60, 31, 10, 8, 16, 13, 66, 18, 24, 11, 70, 9, 72, 37, 10, 20, 16, 15, 78, 9, 8, 41 (list; graph; listen)

	OFFSET	`1,3`
	COMMENT	`a(p) = p-1 for prime p.` `a(n)=A001222(A130279(n))/2. - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), May 21 2007` `This function is not additive; the smallest counterexample is a(40) = 7 != 4 + 4 = a(5) + a(8). - Franklin T. Adams-Watters (FrankTAW(AT)Netscape.net) Jul 10 2009`
	FORMULA	`a(n) = Omega(A005179(n)), where Omega(n) = A001222(n).`
	MATHEMATICA	`s = { (* terms in A005179 *) }; f[n_] := Plus @@ Last /@ FactorInteger@n; f /@ s - Robert G. Wilson v, Aug 31 2006`
	CROSSREFS	`Sequence in context: A089265 A113885 A113886 this_sequence A067240 A126080 A060681` `Adjacent sequences: A122373 A122374 A122375 this_sequence A122377 A122378 A122379`
	KEYWORD	`nonn`
	AUTHOR	`Lekraj Beedassy (blekraj(AT)yahoo.com), Aug 30 2006`
	EXTENSIONS	`More terms from Robert G. Wilson v, Aug 31 2006` `Edited and extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Sep 11 2006` `Incorrect comment removed by Franklin T. Adams-Watters (FrankTAW(AT)Netscape.net), Jul 11 2009`

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Last modified December 2 11:54 EST 2009. Contains 167921 sequences.

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