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A161324 Let b(n,k) = the k-th binary digit (starting at k=1, reading right to left) in the base 2 representation of n. (So: n = sum{k>=0} b(k+1)*2^k.) A positive integer n is included in this sequence if and only if n = product{k>=1} k^b(n,k). 0

%I

%S 1,2,6,12,576000

%N Let b(n,k) = the k-th binary digit (starting at k=1, reading right to left) in the base 2 representation of n. (So: n = sum{k>=0} b(k+1)*2^k.) A positive integer n is included in this sequence if and only if n = product{k>=1} k^b(n,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 in binary is 1100. 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

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Last modified November 15 06:11 EST 2019. Contains 329144 sequences. (Running on oeis4.)