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A103655 Indices of primes which are the average of two successive semiprimes. 4


%S 3,16,19,24,30,32,40,47,54,62,63,68,75,80,87,93,94,95,115,124,126,129,

%T 133,136,138,157,160,162,167,169,175,177,179,187,196,205,222,232,233,

%U 239,240,247,258,265,267,270,274,277,279,298,299,318,327,335,336,339

%N Indices of primes which are the average of two successive semiprimes.

%H Zak Seidov, <a href="/A103655/b103655.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n)=pi(A103654(n)).

%e 19 is a member because p(19)=67; 65 and 69 are two successive semiprimes closest to 67 and 67=(65+69)/2.

%Y Corresponding primes: A103654. Primes: A000040, semiprimes: A001358, number of primes between two successive semiprimes: A088700, number of semiprimes between two successive primes: A103668.

%Y Cf. A000040, A088700, A103654, A001358, A103668, A103669.

%K nonn

%O 1,1

%A _Zak Seidov_, Feb 12 2005

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Last modified December 13 09:54 EST 2019. Contains 329968 sequences. (Running on oeis4.)