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%I #14 Feb 16 2021 02:08:14
%S 38,46,106,129,133,145,201,203,235,291,298,334,335,381,407,417,458,
%T 489,497,538,579,583,597,623,626,649,685,689,694,707,758,767,781,815,
%U 898,899,921,926,959,995,1073,1079,1082,1094,1099,1139,1142,1157,1214,1226
%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.
%e 38 is a term because 38 = 2*19, 2*38 + 1 = 77 = 7*11, and 4*38 + 1 = 155 = 5*31.
%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, 1000}]; lst
%Y Cf. A006881, A111153, A177210, A177211, A177212, A177213, A177214, A177215, A177216, A177217, A177220, A177221.
%Y Cf. A133123 (allows squares also).
%K nonn
%O 1,1
%A _Vladimir Joseph Stephan Orlovsky_, May 05 2010
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