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 A300912 Numbers of the form prime(x)*prime(y) where x and y are relatively prime. 12
 4, 6, 10, 14, 15, 22, 26, 33, 34, 35, 38, 46, 51, 55, 58, 62, 69, 74, 77, 82, 85, 86, 93, 94, 95, 106, 118, 119, 122, 123, 134, 141, 142, 143, 145, 146, 155, 158, 161, 166, 177, 178, 187, 194, 201, 202, 205, 206, 209, 214, 215, 217, 218, 219, 221, 226, 249 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Andrew Howroyd, Table of n, a(n) for n = 1..10000 EXAMPLE The sequence of all relatively prime pairs (columns) begins:   1  1  1  1  2  1  1  2  1  3  1  1  2  3  1  1  2  1  4  1  3  1  2  1  3   1  2  3  4  3  5  6  5  7  4  8  9  7  5 10 11  9 12  5 13  7 14 11 15  8 MATHEMATICA Select[Range[100], And[PrimeOmega[#]==2, GCD@@PrimePi/@If[#==1, {}, FactorInteger[#]][[All, 1]]==1]&] With[{nn=40}, Join[{4}, Take[Prime[#[[1]]]Prime[#[[2]]]&/@Select[Subsets[ Range[ nn], {2}], CoprimeQ@@#&]//Union, Floor[Prime[nn]/2]]]] (* Harvey P. Dale, Jan 04 2021 *) PROG (PARI) ok(n)={my(f=factor(n)); bigomega(f)==2 && gcd(apply(primepi, f[, 1]))==1} \\ Andrew Howroyd, Oct 26 2018 CROSSREFS Cf. A001358, A000837, A001221, A001222, A006881, A289508, A289509, A318990. Sequence in context: A268185 A065073 A084997 * A175706 A110507 A224467 Adjacent sequences:  A300909 A300910 A300911 * A300913 A300914 A300915 KEYWORD nonn AUTHOR Gus Wiseman, Sep 06 2018 STATUS approved

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Last modified January 21 07:11 EST 2021. Contains 340333 sequences. (Running on oeis4.)