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A143202
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Numbers having exactly two distinct prime factors p, q with q=p+2.
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5
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15, 35, 45, 75, 135, 143, 175, 225, 245, 323, 375, 405, 675, 875, 899, 1125, 1215, 1225, 1573, 1715, 1763, 1859, 1875, 2025, 3375, 3599, 3645, 4375, 5183, 5491, 5625, 6075, 6125, 6137, 8575, 9375, 10125, 10403, 10935, 11663, 12005, 16875, 17303, 18225
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OFFSET
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1,1
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COMMENTS
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LINKS
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EXAMPLE
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MATHEMATICA
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tdpfQ[n_]:=Module[{fi=FactorInteger[n][[;; , 1]]}, Length[fi]==2&&fi[[2]]-fi[[1]]==2]; Select[Range[20000], tdpfQ] (* Harvey P. Dale, Mar 04 2023 *)
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PROG
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(Haskell)
a143202 n = a143202_list !! (n-1)
a143202_list = filter (\x -> a006530 x - a020639 x == 2) [1, 3..]
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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