A129089 - OEIS

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A129089

a(0)=a(1)=1. a(n) = GCD(a(n-1),n) + GCD(a(n-2),n).

1, 1, 2, 2, 4, 2, 4, 2, 6, 4, 4, 2, 6, 2, 4, 2, 6, 2, 8, 2, 6, 4, 4, 2, 6, 2, 4, 2, 6, 2, 8, 2, 10, 2, 4, 2, 6, 2, 4, 2, 6, 2, 8, 2, 6, 4, 4, 2, 6, 2, 4, 2, 6, 2, 8, 2, 10, 2, 4, 2, 6, 2, 4, 2, 6, 2, 8, 2, 6, 4, 4, 2, 6, 2, 4, 2, 6, 2, 8, 2, 10, 2, 4, 2, 6, 2, 4, 2, 6, 2, 8, 2, 6, 4, 4, 2, 6, 2, 4, 2, 6, 2, 8, 2 (list; graph; refs; listen; history; internal format)

	OFFSET	`0,3`
	COMMENTS	`a(n) is even for all n >=2.`
	MAPLE	`a[0]:=1: a[1]:=1: for n from 2 to 130 do a[n]:=igcd(a[n-1], n)+igcd(a[n-2], n) od: seq(a[n], n=0..130); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Apr 16 2007`
	CROSSREFS	`Cf. A129088.` `Sequence in context: A092520 A147848 A193432 * A169594 A124315 A101113` `Adjacent sequences: A129086 A129087 A129088 * A129090 A129091 A129092`
	KEYWORD	`nonn`
	AUTHOR	`Leroy Quet Mar 29 2007`
	EXTENSIONS	`More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Apr 16 2007`

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Last modified February 17 00:09 EST 2012. Contains 205978 sequences.