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A063538
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Numbers n that are not sqrt(n-1)-smooth: largest prime factor of n (=A006530(n)) >= sqrt(n).
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6
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2, 3, 4, 5, 6, 7, 9, 10, 11, 13, 14, 15, 17, 19, 20, 21, 22, 23, 25, 26, 28, 29, 31, 33, 34, 35, 37, 38, 39, 41, 42, 43, 44, 46, 47, 49, 51, 52, 53, 55, 57, 58, 59, 61, 62, 65, 66, 67, 68, 69, 71, 73, 74, 76, 77, 78, 79, 82, 83, 85, 86, 87, 88, 89, 91
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refs;
listen;
history;
text;
internal format)
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OFFSET
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1,1
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REFERENCES
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D. H. Greene and D. E. Knuth, Mathematics for the Analysis of Algorithms; see pp. 95-98.
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LINKS
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Robert Israel, Table of n, a(n) for n = 1..10000
Beeler, M., Gosper, R. W. and Schroeppel, R., HAKMEM, ITEM 29
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MAPLE
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N:= 1000: # to get all terms <= N
Primes:= select(isprime, [2, seq(2*i+1, i=1..floor((N-1)/2))]):
S:= {seq(seq(m*p, m = 1 .. min(p, N/p)), p=Primes)}:
sort(convert(S, list)); # Robert Israel, Sep 01 2015
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MATHEMATICA
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Select[Range[2, 91], FactorInteger[#][[-1, 1]] >= Sqrt[#] &] (* Ivan Neretin, Aug 30 2015 *)
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CROSSREFS
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Cf. A006530, A063762.
Complement of A063539. Supersequence of A001358 (semiprimes).
Sequence in context: A210490 A166155 A325457 * A167207 A037143 A236105
Adjacent sequences: A063535 A063536 A063537 * A063539 A063540 A063541
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KEYWORD
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nonn,easy
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AUTHOR
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N. J. A. Sloane, Aug 14 2001
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STATUS
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approved
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