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%I #13 Jun 06 2019 02:44:02
%S 3,1,3,1,3,7,3,5,3,3,1,19,3,11,3,3,3,31,17,3,37,5,3,3,7,3,13,3,5,3,1,
%T 3,3,5,3,19,79,41,3,3,3,7,3,97,3,5,53,7,3,5,3,3,11,3,3,3,3,17,139,3,
%U 71,3,7,3,157,3,83,13,3,5,3,3,23,11,5,3,3,199,3,5,3,211,3,7,5,3,3
%N Least odd prime divisor of prime(n) + 1, or 1 if prime(n) + 1 is a power of 2.
%C Note that a(n) = 1 for n= 2, 4, 11, 31, 1028, ... (A059305). - _Michel Marcus_, Oct 01 2013
%F a(n) = A078701(A008864(n)). - _Michel Marcus_, Jun 06 2019
%o (PARI) a(n) = my(p = prime(n) + 1, v = p/(2^valuation(p, 2))) ; if (v == 1, 1, factor(v)[1, 1]); \\ _Michel Marcus_, Oct 01 2013
%Y Cf. A008864, A078701.
%K nonn
%O 1,1
%A _Clark Kimberling_
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