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%I #8 Feb 10 2016 18:02:37
%S 213,215,299,411,1133,1135,1343,1345,1383,1385,1387,1685,1793,1835,
%T 1837,1891,1937,1939,1957,2045,2315,2317,2513,2567,2807,2809,2929,
%U 3091,3093,3095,3097,3147,3149,3647,3957,3977,3979,4115,4313,4315,4411,4529,4531
%N Numbers n such that n, n+2, n+4, n+6 are semiprimes.
%C Semiprimes in arithmetic progression. All terms are odd, see also A056809.
%H Harvey P. Dale, <a href="/A092126/b092126.txt">Table of n, a(n) for n = 1..1000</a>
%t PrimeFactorExponentsAdded[n_] := Plus @@ Flatten[Table[ #[[2]], {1}] & /@ FactorInteger[n]]; Select[ Range[ 4626], PrimeFactorExponentsAdded[ # ] == PrimeFactorExponentsAdded[ # + 2] == PrimeFactorExponentsAdded[ # + 4] == PrimeFactorExponentsAdded[ # + 6] == 2 &] (* _Robert G. Wilson v_, Feb 24 2004 *)
%t Transpose[SequencePosition[Table[If[PrimeOmega[n]==2,1,0],{n,5000}],{1,_,1,_,1,_,1}]][[1]] (* The program uses the SequencePosition function from Mathematica version 10 *) (* _Harvey P. Dale_, Feb 10 2016 *)
%Y Cf. A056809, A070552, A092125, A092127, A092128, A092129.
%K easy,nonn
%O 1,1
%A _Zak Seidov_, Feb 22 2004