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A123906
a(n) = n-th integer from among those positive integers with at least n positive divisors.
0
1, 3, 8, 12, 24, 30, 54, 56, 100, 120, 144, 150, 288, 300, 324, 360, 560, 576, 756, 780, 990, 1020, 1050, 1056, 1980, 2040, 2100, 2184, 2352, 2376, 2808, 2856, 3900, 3960, 4032, 4080, 6000, 6048, 6120, 6160, 7980, 8064, 8400, 8568, 8580, 9000, 9072, 9120
OFFSET
1,2
EXAMPLE
The sequence of positive integers, each with 4 or more positive divisors, begins: 6,8,10,12,14,... The 4th of these is 12, so a(4) = 12.
MATHEMATICA
f[n_] := Block[{k = 0, c = n}, While[c > 0, k++; While[Length@Divisors[k] < n, k++ ]; c--; ]; k]; Table[f[n], {n, 50}] (* Ray Chandler, Nov 13 2006 *)
CROSSREFS
Sequence in context: A007434 A379717 A128303 * A065970 A326890 A024463
KEYWORD
nonn
AUTHOR
Leroy Quet, Oct 28 2006
EXTENSIONS
Extended by Ray Chandler, Nov 13 2006
STATUS
approved