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

Author

Ray Chandler, Jan 10 2012

Keywords

• nonn

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).

Crossrefs

Cf. A004767, A018782, A204046, A078714.

Formula

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

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