A204086 Least term of A004767 with exactly 2n divisors.

3, 15, 63, 135, 567, 315, 5103, 1155, 1575, 2835, 413343, 4095, 3720087, 25515, 14175, 10395, 301327047, 20475, 2711943423, 36855, 127575, 2066715, 219667417263, 51975, 354375, 18600435, 121275, 331695, 160137547184727, 184275, 1441237924662543, 135135

Offset

1,1

Comments

For odd prime p, a(p) = 3^(p-1)*7.

Links

Ray Chandler, Table of n, a(n) for n = 1..2098 (a(2099) exceeds 1000 digits).

Formula

a(n) = min{d|n: A018782(d) * A204046(n/d)}.

a(n) = 4*A078714(n)-1.

Crossrefs

Cf. A004767, A018782, A204046, A078714.

Sequence in context: A369248 A364585 A260326 * A171761 A229277 A218313

Adjacent sequences: A204083 A204084 A204085 * A204087 A204088 A204089

Keyword

nonn

Author

Ray Chandler, Jan 10 2012

Status

approved