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A090972
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Least k such that there are at least n primes between n and n*k.
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0
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3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 6, 6, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8
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OFFSET
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1,1
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COMMENTS
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a(9) = 5 is saying that there are 9 primes between 9 and 45, but actually there are 10: 11, 13, 17, 19, 23, 29, 31, 37, 41, 43. - Michel Marcus, Nov 20 2017
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LINKS
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EXAMPLE
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a(11) = 5 as there are 11 primes (13,17,19,23,29,31,37,41,43,47,53) between 11 and 55.
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PROG
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(PARI) a(n) = {k=2; while(sum(i=n+1, k*n-1, isprime(i)) < n, k++); k; } \\ Michel Marcus, Nov 22 2017
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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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