%I #17 Apr 14 2021 05:24:41
%S 1,2,6,12,576000
%N Let b(m,k) be the k-th binary digit (starting at k=1, reading right to left) in the base-2 representation of m. (So: n = Sum_{k>=0} b(k+1)*2^k.) A positive integer m is included in this sequence if and only if m = Product_{k>=1} k^b(m,k).
%C Hans Havermann found term a(5).
%C Jack Brennen says that there are no other terms < 2^32.
%C a(6) > 2^80 if it exists. - _Bert Dobbelaere_, Apr 19 2019
%e 12 = 1100_2. And 12 = 4^1 * 3^1 * 2^0 * 1^0. So 12 is in the sequence.
%K base,more,nonn
%O 1,2
%A _Leroy Quet_, Jun 07 2009