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Numbers that are products of distinct terms in A000312.
4

%I #9 Nov 24 2020 10:25:11

%S 1,4,27,108,256,1024,3125,6912,12500,27648,46656,84375,186624,337500,

%T 800000,823543,1259712,3200000,3294172,5038848,11943936,16777216,

%U 21600000,22235661,47775744,67108864,86400000,88942644,145800000,210827008,322486272,387420489,452984832

%N Numbers that are products of distinct terms in A000312.

%H Amiram Eldar, <a href="/A156223/b156223.txt">Table of n, a(n) for n = 1..10000</a>

%e a(1) = 1 = 1^1.

%e a(2) = 4 = 2^2.

%e a(3) = 108 = 2^2 * 3^3.

%e ...

%e a(20) = 5038848 = 2^2 * 3^3 * 6^6.

%t 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 *)

%Y Cf. A000312.

%K nonn

%O 1,2

%A _Gabriel C. Benamy_, Feb 06 2009

%E More terms from _Amiram Eldar_, Nov 24 2020