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A163127 a(1)=1. a(n) is the number of integers k, 1 <= k <= n-1, where gcd(a(k), n-k) >= 2. 1

%I

%S 1,0,0,1,2,2,3,3,3,4,4,5,5,5,5,5,6,6,7,8,8,8,8,9,9,11,11,10,9,11,10,

%T 12,14,12,13,14,14,16,14,17,16,15,18,17,18,18,20,20,21,18,20,23,23,22,

%U 22,23,24,22,24,25,28,24,29,23,28,27,28,26,29,26,30,30,31,32,33,31,32,31

%N a(1)=1. a(n) is the number of integers k, 1 <= k <= n-1, where gcd(a(k), n-k) >= 2.

%C For the purpose of this sequence, gcd(m,0) is considered to be m.

%Y Cf. A163126.

%K nonn

%O 1,5

%A _Leroy Quet_, Jul 21 2009

%E More terms from _Sean A. Irvine_, Oct 20 2009

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Last modified May 25 09:45 EDT 2022. Contains 354066 sequences. (Running on oeis4.)