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A157941
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Numbers n divisible by the largest prime < sqrt(n), A007917(A000196(n-1)).
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4
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6, 8, 12, 15, 18, 21, 24, 30, 35, 40, 45, 56, 63, 70, 77, 84, 91, 98, 105, 112, 119, 132, 143, 154, 165, 182, 195, 208, 221, 234, 247, 260, 273, 286, 306, 323, 340, 357, 380, 399, 418, 437, 456, 475, 494, 513, 552, 575, 598, 621, 644, 667, 690, 713, 736, 759
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OFFSET
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1,1
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COMMENTS
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Includes products of pairs of consecutive primes (A006094) as subsequence, equals A157942 with squares of primes (A001248) removed.
For a number < 5 the definition does not make much sense, since there is no prime < sqrt(4) = 2, so we don't consider them here.
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LINKS
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MATHEMATICA
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Select[Range[6, 800], Divisible[#, NextPrime[Sqrt[#], -1]]&] (* Harvey P. Dale, Sep 14 2019 *)
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PROG
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(PARI) for( n=5, 999, n % precprime(sqrtint(n-1)) | print1(n", "))
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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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