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A141198 a(n) = the number of divisors of n that are each one more than a power of a prime. 2

%I

%S 0,1,1,2,1,3,0,3,2,3,0,5,0,2,2,3,1,5,0,5,1,1,0,7,1,2,2,4,0,6,0,4,2,2,

%T 1,7,0,2,1,6,0,5,0,3,3,1,0,8,0,4,2,3,0,6,1,5,1,1,0,10,0,2,2,4,2,4,0,4,

%U 1,4,0,10,0,2,2,3,0,4,0,7,2,2,0,9,2,1,1,4,0,9,0,2,1,1,1,9,0,3,3,6,0,5,0

%N a(n) = the number of divisors of n that are each one more than a power of a prime.

%C 1 is considered here to be a power of a prime. 0 is not considered here to be a power of a prime.

%H Diana Mecum, <a href="/A141198/b141198.txt">Table of n, a(n) for n = 1..1049</a>

%e The divisors of 9 are 1,3,9. 1 is one more than 0, not a power of a prime. 3 is one more than 2, a power of a prime. And 9 is one more than 8, a power of a prime. There are therefore 2 such divisors that are each one more than a power of a prime. So a(9)=2.

%Y Cf. A141197.

%K nonn

%O 1,4

%A _Leroy Quet_, Jun 12 2008

%E Corrected and extended by _Diana L. Mecum_, Jul 05 2007

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Last modified July 2 16:02 EDT 2020. Contains 335404 sequences. (Running on oeis4.)