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
Keywords
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