%I A107347
%S A107347 0,1,1,1,1,2,2,3,3,3,4,4,4,5,5,6,6,7,7,8,9,9,9,9,9,10,11,11,12,13,12,13,
%T A107347 13,14,13,14,15,15,15,16,16,17,18,19,19,20,19,18,18,19,20,21,22,23,23,
%U A107347 23,24,25,25,25,26,27,26,27,28,28,28,28,28,29,30,30,30,31,32,32,32,32
%N A107347 Number of even semiprimes strictly between p and 2p.
%t A107347 fQ[n_] := Plus @@ Last /@ FactorInteger[n] == 2; f[n_] := Count[fQ /@ 
               Range[Prime[n] + 1, Prime[n + 1] - 1], True]; Table[ f[n], {n, 78}] 
               (from Robert G. Wilson v (rgwv(AT)rgwv.com), May 28 2005)
%Y A107347 Sequence in context: A057360 A057364 A060144 this_sequence A163127 A077113 
               A143796
%Y A107347 Adjacent sequences: A107344 A107345 A107346 this_sequence A107348 A107349 
               A107350
%K A107347 nonn
%O A107347 1,6
%A A107347 Giovanni Teofilatto (g.teofilatto(AT)tiscalinet.it), May 23 2005
%E A107347 Corrected and extended by Robert G. Wilson v (rgwv(AT)rgwv.com), May 
               28 2005