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A126253
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a(n) = n-th integer from among those positive integers which are each coprime to exactly one prime dividing n.
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0
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3, 4, 7, 6, 10, 8, 15, 13, 18, 12, 22, 14, 26, 36, 31, 18, 34, 20, 38, 54, 42, 24, 46, 31, 50, 40, 54, 30, 130, 32, 63, 88, 66, 120, 70, 38, 74, 105, 78, 42, 192, 44, 86, 111, 90, 48, 94, 57, 98, 141, 102, 54, 106, 210, 110, 159, 114, 60, 255, 62, 122, 162
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OFFSET
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2,1
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LINKS
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EXAMPLE
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The positive integers which are each coprime to exactly one prime dividing 12 form the sequence: 2,3,4,8,9,10,14,15,16,20,21,22,26,27,28... The 12th of these is 22; so a(12) = 22.
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PROG
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(PARI) a(n) = {ok = 0; nb = 0; i = 1; pf = factor(n)[, 1]; while(! ok, if (sum(j=1, #pf, gcd(i, pf[j]) == 1) == 1, nb++); if (nb == n, ok = 1, i++); ); i; } \\ Michel Marcus, Feb 10 2014
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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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