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 A248597 a(n) = A248595(n) - prime(n)*A248596(n). 1

%I

%S 1,1,1,2,1,2,2,2,1,1,2,2,1,2,4,1,2,2,2,4,2,2,1,1,2,4,2,2,2,1,2,1,4,2,

%T 2,2,2,2,2,1,1,2,1,2,2,2,4,2,2,4,1,1,6,1,2,4,2,4,2,1,6,1,4,4,2,2,2,2,

%U 4,2,2,1,2,2,4,2,4,2,10,2,1,6,1,2,2,1

%N a(n) = A248595(n) - prime(n)*A248596(n).

%C If a(n)=1 then prime(n) is a Sophie Germain prime.

%C Except for Sophie Germain primes a(n) is always even.

%C Conjecture: all even numbers are present many times in A248597(n) and any even number may be written in many ways as the difference between a prime Q and a product of two primes P*R.

%H Pierre CAMI, <a href="/A248597/b248597.txt">Table of n, a(n) for n = 1..10000</a>

%Y Cf. A005384 (Sophie Germain primes), A248595, A248596.

%K nonn

%O 1,4

%A _Pierre CAMI_, Oct 09 2014

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Last modified January 24 04:35 EST 2020. Contains 331183 sequences. (Running on oeis4.)