Search: id:A107347 Results 1-1 of 1 results found. %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 Search completed in 0.001 seconds