%I A005381 M4598
%S A005381 9,10,15,16,21,22,25,26,27,28,33,34,35,36,39,40,45,46,49,50,51,52,55,
%T A005381 56,57,58,63,64,65,66,69,70,75,76,77,78,81,82,85,86,87,88,91,92,93,94,
               95
%N A005381 Numbers n such that n and n-1 are composite.
%C A005381 Position where the composites first outnumber the primes by n, among 
               the first natural numbers. - Lekraj Beedassy (blekraj(AT)yahoo.com), 
               Jul 11 2006
%D A005381 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%D A005381 M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, 
               National Bureau of Standards Applied Math. Series 55, 1964 (and various 
               reprintings), p. 844.
%H A005381 M. Abramowitz and I. A. Stegun, eds., <a href="http://www.nrbook.com/
               abramowitz_and_stegun/">Handbook of Mathematical Functions</a>, National 
               Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 
               [alternative scanned copy].
%Y A005381 Equals A068780 + 1. Cf. A007921.
%Y A005381 Sequence in context: A088710 A020199 A114844 this_sequence A099616 A140209 
               A073829
%Y A005381 Adjacent sequences: A005378 A005379 A005380 this_sequence A005382 A005383 
               A005384
%K A005381 nonn,easy
%O A005381 1,1
%A A005381 N. J. A. Sloane (njas(AT)research.att.com).