%I A157483
%S A157483 19,29,43,51,67,69,77,115,171,173,187,189,237,243,245,267,274,283,285,
%T A157483 291,317,344,355,386,403,405,411,424,427,429,435,437,476,507,597,603,
%U A157483 604,605,638,653,664,669,723,763,776,787,789,846,891,893,907,926,963
%N A157483 Numbers n such that n-+1 are divisible by exactly 3 primes, counted with 
               multiplicity.
%C A157483 18=2*3*3,20=2*2*5, ...
%p A157483 with(numtheory); a := proc (n) if bigomega(n-1) = 3 and bigomega(n+1) 
               = 3 then n else end if end proc: seq(a(n), n = 2 .. 1100); [From 
               Emeric Deutsch (deutsch(AT)duke.poly.edu), Mar 03 2009]
%t A157483 q=3;lst={};Do[If[Plus@@Last/@FactorInteger[n-1]==q&&Plus@@Last/@FactorInteger[n+1]==q,
               AppendTo[lst,n]],{n,7!}];lst
%Y A157483 Cf. A124936, A014612, A156028
%Y A157483 Sequence in context: A158846 A157026 A108183 this_sequence A096218 A100590 
               A046120
%Y A157483 Adjacent sequences: A157480 A157481 A157482 this_sequence A157484 A157485 
               A157486
%K A157483 nonn
%O A157483 1,1
%A A157483 Vladimir Orlovsky (4vladimir(AT)gmail.com), Mar 01 2009
%E A157483 More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Mar 03 2009