A166305 Even semiprimes k such that the largest prime factor + 8 is a prime. Also semiprimes k such that k+16 is semiprime.
6, 10, 22, 46, 58, 106, 118, 142, 178, 202, 262, 298, 346, 382, 466, 526, 538, 718, 778, 802, 862, 898, 958, 982, 1126, 1138, 1186, 1198, 1306, 1366, 1402, 1438, 1486, 1522, 1642, 1822, 1858, 1966, 2026, 2062, 2122, 2218, 2326, 2386, 2446, 2458, 2566, 2578
Offset: 1
Keywords
Programs
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Maple
A006530 := proc(n) numtheory[factorset](n) ; max(op(%)) ; end proc: isA166305 := proc(n) if type(n,'even') then if numtheory[bigomega](n) = 2 then isprime(A006530(n)+8) ; else false; end if; else false; end if; end proc: for n from 4 to 3000 by 2 do if isA166305(n) then printf("%d,",n) ; end if; end do: # R. J. Mathar, Jan 30 2010
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Mathematica
Select[2*Range[1500],PrimeOmega[#]==PrimeOmega[#+16]==2&] (* Harvey P. Dale, Dec 28 2013 *)
Extensions
Extended by R. J. Mathar, Jan 30 2010