A070077 - OEIS

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A070077

Greatest common divisor of n-th squarefree number and n-th cube-free number.

1, 2, 3, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 3, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 3, 1, 3, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 5, 1, 1, 2, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 2, 1, 1, 3, 2, 1, 1, 2, 1, 2, 1, 3, 1, 1, 1 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	COMMENTS	`a(n) is squarefree;` `Conjecture: for any squarefree k exists m such that a(m)=k; see A070078.`
	LINKS	`Eric Weisstein's World of Mathematics, squarefree numbers.` `Eric Weisstein's World of Mathematics, cube-free numbers.`
	FORMULA	`a(n) = GCD(A005117(n), A004709(n)).`
	EXAMPLE	`a(10)=GCD(A005117(10), A004709(10))=GCD(14,11)=1.` `a(11)=GCD(A005117(11), A004709(11))=GCD(15,12)=3GCD(5,4)=31=3.`
	CROSSREFS	`Sequence in context: A004579 A081371 A027870 * A122587 A086195 A086197` `Adjacent sequences: A070074 A070075 A070076 * A070078 A070079 A070080`
	KEYWORD	`nonn`
	AUTHOR	`Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Apr 22 2002`

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Last modified February 13 19:38 EST 2012. Contains 205536 sequences.