id:A078898 - OEIS Search Results

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Number of times the smallest prime factor of n is the smallest prime factor for numbers <=n; a(1)=1.

+0
3

1, 1, 1, 2, 1, 3, 1, 4, 2, 5, 1, 6, 1, 7, 3, 8, 1, 9, 1, 10, 4, 11, 1, 12, 2, 13, 5, 14, 1, 15, 1, 16, 6, 17, 3, 18, 1, 19, 7, 20, 1, 21, 1, 22, 8, 23, 1, 24, 2, 25, 9, 26, 1, 27, 4, 28, 10, 29, 1, 30, 1, 31, 11, 32, 5, 33, 1, 34, 12, 35, 1, 36, 1, 37, 13, 38, 3, 39, 1, 40, 14, 41, 1, 42, 6, 43 (list; graph; listen)

	OFFSET	`1,4`
	COMMENT	`For n>1: a(n)=1 iff n is prime;` `a(2*n) = n.`
	FORMULA	`Ordinal transform of A020639 (Lpf). - Frank Adams-Watters (FrankTAW(AT)Netscape.net), Aug 28 2006`
	CROSSREFS	`Cf. A020639, A078899, A078896.` `Adjacent sequences: A078895 A078896 A078897 this_sequence A078899 A078900 A078901` `Sequence in context: A117172 A029207 A111902 this_sequence A130747 A055440 A101279`
	KEYWORD	`nonn`
	AUTHOR	`Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Dec 12 2002`

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Last modified October 15 09:18 EDT 2008. Contains 145015 sequences.

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