cp's OEIS Frontend

A300558 a(n) is the concatenation n written in base 2 n times, n-1 written in base 2 n-1 times, ..., 1 written in base 2 once.

%I A300558 #17 Mar 09 2018 06:06:18
%S A300558 1,10101,11111110101,10010010010011111110101,
%T A300558 10110110110110110010010010011111110101,
%U A300558 11011011011011011010110110110110110010010010011111110101,11111111111111111111111011011011011011010110110110110110010010010011111110101
%N A300558 a(n) is the concatenation n written in base 2 n times, n-1 written in base 2 n-1 times, ..., 1 written in base 2 once.
%H A300558 Seiichi Manyama, <a href="/A300558/b300558.txt">Table of n, a(n) for n = 1..21</a>
%o A300558 (Ruby)
%o A300558 def A300558(n)
%o A300558   a = '1'
%o A300558   [1] + (2..n).map{|i| a = (i.to_s(2) * i + a.to_s).to_i}
%o A300558 end
%o A300558 p A300558(10)
%Y A300558 Cf. A007088, A300517, A300557.
%K A300558 nonn,base
%O A300558 1,2
%A A300558 _Seiichi Manyama_, Mar 08 2018