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A126253
a(n) = n-th integer from among those positive integers which are each coprime to exactly one prime dividing n.
0
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
OFFSET
2,1
EXAMPLE
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.
PROG
(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
CROSSREFS
Sequence in context: A087030 A175187 A332993 * A057032 A347529 A279388
KEYWORD
nonn
AUTHOR
Leroy Quet, Mar 08 2007
EXTENSIONS
Offset corrected and more terms from Michel Marcus, Feb 10 2014
STATUS
approved