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 A138309 a(1)=1. a(n) = smallest integer > a(n-1) that is coprime to every (nonzero) exponent in the prime factorization of n. 2

%I #7 Apr 09 2014 10:13:43

%S 1,2,3,5,6,7,8,10,11,12,13,15,16,17,18,19,20,21,22,23,24,25,26,28,29,

%T 30,31,33,34,35,36,37,38,39,40,41,42,43,44,46,47,48,49,51,53,54,55,57,

%U 59,61,62,63,64,65,66,67,68,69,70,71,72,73,75,77,78,79,80,81,82,83,84,85

%N a(1)=1. a(n) = smallest integer > a(n-1) that is coprime to every (nonzero) exponent in the prime factorization of n.

%e 24 has the prime-factorization of 2^3 * 3^1. The smallest integer > a(23)=26 that is coprime to 3 and 1 is 28. (27 is not coprime to 3.) So a(24)=28.

%Y Cf. A138308, A138311.

%K nonn

%O 1,2

%A _Leroy Quet_, Mar 13 2008

%E More terms from _Sean A. Irvine_, Mar 07 2010

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Last modified September 9 10:46 EDT 2024. Contains 375764 sequences. (Running on oeis4.)