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1,3

a(2n) is odd for all n >=1. a(2n-1) is even for all n >=2.

Table of n, a(n) for n=1..105.

a[1]:=1: a[2]:=1: for n from 3 to 140 do a[n]:=gcd(a[n-1], n)+gcd(a[n-2], n) od: seq(a[n], n=1..140); - Emeric Deutsch, Apr 04 2007

Cf. A129089.

Sequence in context: A101876 A260218 A087986 * A086418 A100761 A027748

Adjacent sequences: A129085 A129086 A129087 * A129089 A129090 A129091

nonn

Leroy Quet, Mar 29 2007

More terms from Emeric Deutsch, Apr 04 2007

approved