id:A014673 - OEIS Search Results

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Smallest prime factor of greatest proper divisor of n.

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1, 1, 1, 2, 1, 3, 1, 2, 3, 5, 1, 2, 1, 7, 5, 2, 1, 3, 1, 2, 7, 11, 1, 2, 5, 13, 3, 2, 1, 3, 1, 2, 11, 17, 7, 2, 1, 19, 13, 2, 1, 3, 1, 2, 3, 23, 1, 2, 7, 5, 17, 2, 1, 3, 11, 2, 19, 29, 1, 2, 1, 31, 3, 2, 13, 3, 1, 2, 23, 5, 1, 2, 1, 37, 5, 2, 11, 3, 1, 2, 3, 41, 1, 2, 17, 43, 29, 2, 1, 3, 13, 2, 31, 47 (list; graph; listen)

	OFFSET	`1,4`
	COMMENT	`a(n) = A020639(A032742(n));` `For n>1: a(n) = 1 iff n is prime; a(A001358(n)) = A084127(n); a(A000961(n)) = A020639(A000961(n)).`
	FORMULA	`A117357(n) = A020639(A054576(n)); A117358(n) = A032742(A054576(n)) = A054576(n)/A117357(n). - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Mar 10 2006`
	MATHEMATICA	`PrimeFactors[ n_ ] := Flatten[ Table[ # [ [ 1 ] ], {1} ] & /@ FactorInteger[ n ] ]; f[ n_ ] := Block[ {gpd = Divisors[ n ][ [ -2 ] ]}, If[ gpd == 1, 1, PrimeFactors[ gpd ][ [ 1 ] ] ] ]; Table[ If[ n == 1, 1, f[ n ] ], {n, 1, 95} ]`
	CROSSREFS	`Cf. A085392, A085393.` `Sequence in context: A096107 A128487 A056609 this_sequence A085392 A089384 A144113` `Adjacent sequences: A014670 A014671 A014672 this_sequence A014674 A014675 A014676`
	KEYWORD	`nonn`
	AUTHOR	`Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Jun 24 2003`

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Last modified December 11 12:57 EST 2009. Contains 170656 sequences.

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