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A092129 Numbers n such that n, n+2, n+4, n+6, n+8, n+10, n+12 are semiprimes. 11

%I #10 Oct 14 2018 12:46:22

%S 3091,8129,8131,9983,9985,55559,92603,99443,99445,112709,132077,

%T 132079,182749,190937,190939,209479,237449,237451,239089,249689,

%U 296779,300449,313411,401429,401431,441677,441679,452639,452641,547157,604487,604489

%N Numbers n such that n, n+2, n+4, n+6, n+8, n+10, n+12 are semiprimes.

%C Semiprimes in arithmetic progression. All terms are odd, see also A056809.

%t PrimeFactorExponentsAdded[n_] := Plus @@ Flatten[Table[ #[[2]], {1}] & /@ FactorInteger[n]]; Select[ Range[ 631200], PrimeFactorExponentsAdded[ # ] == PrimeFactorExponentsAdded[ # + 2] == PrimeFactorExponentsAdded[ # + 4] == PrimeFactorExponentsAdded[ # + 6] == PrimeFactorExponentsAdded[ # + 8] == PrimeFactorExponentsAdded[ # + 10] == PrimeFactorExponentsAdded[ # + 12] == 2 &] (* _Robert G. Wilson v_, Feb 24 2004 *)

%t Select[Range[610000],Union[PrimeOmega[#+Range[0,12,2]]]=={2}&] (* _Harvey P. Dale_, Oct 14 2018 *)

%Y Cf. A056809, A070552, A092125, A092126, A092127, A092128.

%K easy,nonn

%O 1,1

%A _Zak Seidov_, Feb 22 2004

%E More terms from _Don Reble_, Feb 23 2004

%E More terms from _Robert G. Wilson v_, Feb 24 2004

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Last modified March 28 17:25 EDT 2024. Contains 371254 sequences. (Running on oeis4.)