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%I #11 May 09 2018 16:54:42
%S 46189,50634,69597,76797,90117,97954,108205,115804,127347,138957,
%T 144627,159340,164020,166022,166497,166705,167205,167485,173194,
%U 174454,181670,186294,190014,193154,198789,211029,212134,214225,217217,221815,222547,224146
%N Numbers n such that n, n+1, and the sum of those two numbers each have 4 or more distinct prime factors.
%H Robert Israel, <a href="/A168630/b168630.txt">Table of n, a(n) for n = 1..10000</a>
%e FactorInteger[46189]=11*13*17*19, FactorInteger[46190]=2*5*31*149, FactorInteger[46189+46190]=3*7*53*83,..
%p g:= proc(n) option remember; nops(numtheory:-factorset(n))>=4 end proc:
%p filter:= n -> g(n) and g(n+1) and g(2*n+1):
%p select(filter, [$1..300000]); # _Robert Israel_, May 09 2018
%t f[n_]:=Length[FactorInteger[n]]; lst={};Do[If[f[n]>=4&&f[n+1]>=4&&f[n+n+1]>=4,AppendTo[lst,n]],{n,9!}];lst
%t Select[Range[225000],Min[Thread[PrimeNu[{#,#+1,2#+1}]]]>3&](* _Harvey P. Dale_, Nov 11 2017 *)
%Y Cf. A140077, A140078, A168626, A168628, A168629
%K nonn
%O 1,1
%A _Vladimir Joseph Stephan Orlovsky_, Dec 01 2009
%E Definition modified and terms extended by _Harvey P. Dale_, Nov 11 2017
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