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A260897 Numerator of det(M) where M is the n X n matrix with M[i,j] = 1/lcm(i,j).

%I A260897 #23 Aug 24 2015 17:28:34
%S A260897 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
%T A260897 2,1,2,1,8,2,16,16,32,8,64,32,64,4,8,8,256,128,512,256,2048,256,1024,
%U A260897 1024,2048,2048,8192,4096,16384,128,2048,2048,4096,8192,32768,65536,131072,16384,131072
%N A260897 Numerator of det(M) where M is the n X n matrix with M[i,j] = 1/lcm(i,j).
%C A260897 All terms are powers of two (A000079).
%H A260897 Robert G. Wilson v, <a href="/A260897/b260897.txt">Table of n, a(n) for n = 1..500</a>
%F A260897 a(n) = 2^A260502(n).
%p A260897 seq(denom(1/LinearAlgebra:-Determinant(Matrix(n,n,1/ilcm))),n=1..100); # _Robert Israel_, Aug 17 2015
%t A260897 f[n_] := Denominator[1 / Det[ Table[ 1/LCM[i, j], {i, n}, {j, n}]]]; Array[f, 73]
%o A260897 (PARI) vector(80, n, denominator(1/matdet(matrix(n, n, i, j, 1/lcm(i, j))))) \\ _Michel Marcus_, Aug 04 2015
%Y A260897 Cf. A060841, A260502.
%K A260897 nonn
%O A260897 1,35
%A A260897 _Robert G. Wilson v_, Aug 03 2015