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Primes p such that there is only one semiprime number between prime(p) and prime(p+1).
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%I #12 Mar 30 2012 18:52:46

%S 2,3,19,29,31,59,73,149,179,199,211,271,281,311,337,347,349,359,433,

%T 449,479,523,547,659,661,683,727,733,809,821,823,829,857,877,947,977,

%U 983,1049,1129,1181,1201,1213,1291,1297,1301,1307,1321,1367,1429,1433,1439,1451,1489,1493,1511,1553,1567

%N Primes p such that there is only one semiprime number between prime(p) and prime(p+1).

%e a(1)=2 because 2 is a prime and prime(2)=3<(only one semiprime 4)<5=prime(2+1), a(2)=3 because 3 is a prime and prime(3)=5<(only one semiprime 6)<7=prime(3+1), a(3)=19 because 19 is a prime and prime(19)=67<(only one semiprime 69)<71=prime(19+1).

%Y Cf. A103668, A001358, A006450, A195190.

%K nonn

%O 1,1

%A _Juri-Stepan Gerasimov_, Sep 17 2011

%E Corrected by R. J. Mathar, Sep 20 2011