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A166063
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23-rough numbers: positive integers that have no prime factors less than 23.
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11
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1, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 283, 293, 307, 311, 313, 317, 331, 337, 347, 349, 353, 359, 367, 373, 379, 383, 389, 397, 401, 409, 419, 421, 431, 433, 439, 443, 449, 457, 461, 463, 467, 479, 487, 491, 499
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OFFSET
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1,2
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COMMENTS
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Or, positive integers relatively prime to 9699690 = 2*3*5*7*11*13*17*19.
First composite term is 529 = 23^2.
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LINKS
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FORMULA
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a(n) = k*n + O(1) where k = 323323/55296 = 5.8471.... In particular, k*n - 51 < a(n) < k*n + 45. - Charles R Greathouse IV, Sep 21 2018
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EXAMPLE
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667 = 23 * 29 is in the sequence since the two prime factors, 23 and 29, are not less than 23.
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MATHEMATICA
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Select[Range[500], FactorInteger[#][[1, 1]]>22&] (* Harvey P. Dale, Nov 22 2010 *)
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PROG
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CROSSREFS
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KEYWORD
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easy,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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