cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A161324 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).

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%I A161324 #17 Apr 14 2021 05:24:41
%S A161324 1,2,6,12,576000
%N A161324 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 A161324 Hans Havermann found term a(5).
%C A161324 Jack Brennen says that there are no other terms < 2^32.
%C A161324 a(6) > 2^80 if it exists. - _Bert Dobbelaere_, Apr 19 2019
%e A161324 12 = 1100_2. And 12 = 4^1 * 3^1 * 2^0 * 1^0. So 12 is in the sequence.
%K A161324 base,more,nonn
%O A161324 1,2
%A A161324 _Leroy Quet_, Jun 07 2009