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A066312
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Numbers, other than prime powers, whose distinct prime factors are consecutive primes.
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20
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6, 12, 15, 18, 24, 30, 35, 36, 45, 48, 54, 60, 72, 75, 77, 90, 96, 105, 108, 120, 135, 143, 144, 150, 162, 175, 180, 192, 210, 216, 221, 225, 240, 245, 270, 288, 300, 315, 323, 324, 360, 375, 384, 385, 405, 420, 432, 437, 450, 480, 486
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internal format)
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OFFSET
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1,1
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COMMENTS
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Numbers whose squarefree kernel (A007947) is the product of 2 or more consecutive primes. - Peter Munn, May 27 2023
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LINKS
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FORMULA
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EXAMPLE
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75 is included because 75 = 3 * 5^2 and 3 and 5 are consecutive primes.
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MATHEMATICA
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Select[Range[2, 500], And[! PrimePowerQ@ #, Union@ Differences@ PrimePi[FactorInteger[#][[All, 1]]] == {1}] &] (* Michael De Vlieger, Sep 24 2017 *)
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PROG
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(PARI) { n=0; for (m=2, 10^9, f=factor(m); b=1; if (matsize(f)[1] == 1, next); for (i=2, matsize(f)[1], if (primepi(f[i, 1]) - primepi(f[i - 1, 1]) > 1, b=0; break)); if (b, write("b066312.txt", n++, " ", m); if (n==1000, return)) ) } \\ Harry J. Smith, Feb 10 2010
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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