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a(n) is the least k > 0 such that k*n does not belong to A002202.
2

%I #9 Jul 12 2018 00:53:01

%S 3,7,1,17,1,15,1,19,1,5,1,43,1,1,1,19,1,5,1,17,1,7,1,167,1,1,1,11,1,3,

%T 1,19,1,1,1,67,1,1,1,17,1,17,1,7,1,5,1,211,1,1,1,7,1,11,1,13,1,3,1,

%U 139,1,1,1,31,1,9,1,1,1,5,1,109,1,1,1,1,1,3,1

%N a(n) is the least k > 0 such that k*n does not belong to A002202.

%C All terms are odd.

%H Rémy Sigrist, <a href="/A316665/b316665.txt">Table of n, a(n) for n = 1..10000</a>

%H Rémy Sigrist, <a href="/A316665/a316665.png">Scatterplot of (x, y) such that 1 <= x, y <= 500 and x*y does not belong to A002202</a>

%F a(n) = 1 iff n belongs to A007617.

%o (PARI) a(n) = forstep (k=1, oo, 2, if (!istotient(n*k), return (k)))

%Y Cf. A002202, A007617.

%K nonn

%O 1,1

%A _Rémy Sigrist_, Jul 10 2018