A139712 - OEIS

A139712

a(1)=1. For n >=2, a(n) = largest positive integer < a(n-1) that is not coprime to n, if such an integer exists. Otherwise, a(n) = smallest integer > a(n-1) that is not coprime to n.

%I #8 Apr 09 2014 10:14:08

%S 1,2,3,2,5,4,7,6,3,2,11,10,13,12,10,8,17,16,19,18,15,14,23,22,20,18,

%T 15,14,29,28,31,30,27,26,25,24,37,36,33,32,41,40,43,42,40,38,47,46,42,

%U 40,39,38,53,52,50,49,48,46,59,58,61,60,57,56,55,54,67,66,63,62,71,70,73

%N a(1)=1. For n >=2, a(n) = largest positive integer < a(n-1) that is not coprime to n, if such an integer exists. Otherwise, a(n) = smallest integer > a(n-1) that is not coprime to n.

%H Diana Mecum, <a href="/A139712/b139712.txt">Table of n, a(n) for n = 1..1021</a>

%Y Cf. A139713.

%K nonn

%O 1,2

%A _Leroy Quet_, Apr 30 2008

%E More terms from _Diana L. Mecum_, Jul 22 2008