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A119932 Triangle of denominators of the cube of a certain lower triangular matrix. 5

%I

%S 1,8,8,108,108,27,576,576,576,64,18000,18000,18000,2000,125,21600,

%T 21600,21600,21600,5400,216,1234800,1234800,1234800,1234800,308700,

%U 12348,343,5644800,5644800,5644800,5644800

%N Triangle of denominators of the cube of a certain lower triangular matrix.

%C The triangle of the corresponding numerators is A119935.

%C See a comment under A119935 on the relation to the triangle A027447.

%H W. Lang: <a href="http://www.itp.kit.edu/~wl/EISpub/A119932.text">First ten rows and rationals.</a>

%F a(i,j)= denominator(r(i,j)) with r(i,j):=(A^3)[i,j], where the lower triangular matrix A has elements a[i,j] = 1/i if j<=i, 0 if j>i.

%Y a(i, j)=1/A002024(i, j), i>=1, j<=i.

%Y Row sums give A119933. Row sums of the triangle of rationals are identical 1.

%K nonn,easy,tabl,frac

%O 1,2

%A _Wolfdieter Lang_, Jul 20 2006

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Last modified April 21 04:56 EDT 2019. Contains 322310 sequences. (Running on oeis4.)