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%I #9 Aug 01 2019 03:49:24
%S 1,1,1,3,1,1,2,3,1,1,1,1,3,1,1,3,1,1,3,1,1,7,3,1,1,3,1,1,4,7,3,1,1,3,
%T 1,1,9,2,7,3,1,1,3,1,1,1,9,1,7,3,1,1,3,1,1,11,1,9,1,7,3,1,1,3,1,1,6,
%U 11,1,9,1,7,3,1,1,3,1,1,13,3,11,1,9,1,7,3,1,1,3,1,1
%N Rectangular array A read by (upward) antidiagonals: A(n,k) = n/gcd(n,10^k), n,k >= 1.
%C Columns of A converge to A132740.
%e Array A begins:
%e 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, ...
%e 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, ...
%e 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, ...
%e 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, ...
%e 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, ...
%e 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, ...
%e 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, ...
%e 4, 2, 1, 1, 1, 1, 1, 1, 1, 1, ...
%e 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, ...
%e ...
%t Grid[Table[n/GCD[n, 10^k], {n, 12}, {k, 12}]] (* Array *)
%t Flatten[Table[(n - k + 1)/GCD[n - k + 1, 10^k], {n, 13}, {k, n}]] (* Array antidiagonals flattened *)
%Y Cf. A132740.
%K nonn,tabl
%O 1,4
%A _L. Edson Jeffery_, Jul 25 2014