A156223 Numbers that are products of distinct terms in A000312.

1, 4, 27, 108, 256, 1024, 3125, 6912, 12500, 27648, 46656, 84375, 186624, 337500, 800000, 823543, 1259712, 3200000, 3294172, 5038848, 11943936, 16777216, 21600000, 22235661, 47775744, 67108864, 86400000, 88942644, 145800000, 210827008, 322486272, 387420489, 452984832

Offset: 1

Author

Gabriel C. Benamy, Feb 06 2009

Keywords

• nonn

Examples

			a(1) = 1 = 1^1.
a(2) = 4 = 2^2.
a(3) = 108 = 2^2 * 3^3.
...
a(20) = 5038848 = 2^2 * 3^3 * 6^6.
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000312.

Programs

Mathematica

seq[max_] := Module[{kmax = 1, s = {1}}, While[kmax^kmax < max, kmax++]; Do[s = Select[Union[s, k^k*s], # <= max &], {k, 1, kmax}]; s]; seq[10^8] (* Amiram Eldar, Nov 24 2020 *)

Extensions

More terms from Amiram Eldar, Nov 24 2020