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%I #10 Feb 16 2021 02:11:25
%S 33,118,119,134,146,226,247,249,287,295,334,335,386,391,393,395,422,
%T 478,493,497,502,519,551,583,589,614,629,634,694,697,721,731,749,755,
%U 789,802,817,843,879,898,955,958,985,989,1003,1037,1079,1114,1154,1159,1177
%N Numbers k that are the products of two distinct primes such that 2*k-1 and 4*k-3 are also products of two distinct primes.
%H Harvey P. Dale, <a href="/A177211/b177211.txt">Table of n, a(n) for n = 1..1000</a>
%e 33 is a term because 33 = 3*11, 2*33 - 1 = 65 = 5*13 and 2*65 - 1 = 4*33 - 3 = 129 = 3*43.
%t f[n_]:=Last/@FactorInteger[n]=={1,1}; lst={};Do[If[f[n]&&f[2*n-1]&&f[4*n-3],AppendTo[lst,n]],{n,0,7!}];lst
%t tdpQ[n_]:=PrimeNu[n]==PrimeOmega[n]==PrimeNu[2n-1]==PrimeOmega[2n-1] == PrimeNu[4n-3]==PrimeOmega[4n-3]==2; Select[Range[1200],tdpQ] (* _Harvey P. Dale_, Nov 15 2020 *)
%Y Cf. A006881, A177210
%K nonn
%O 1,1
%A _Vladimir Joseph Stephan Orlovsky_, May 04 2010
%E Definition clarified by _Harvey P. Dale_, Nov 15 2020
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