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%I #2 Mar 30 2012 18:59:15
%S 1,2,1,24,12,1,720,360,30,1,40320,20160,1680,56,1,3628800,1814400,
%T 151200,5040,90,1,479001600,239500800,19958400,665280,11880,132,1,
%U 87178291200,43589145600,3632428800,121080960,2162160,24024,182,1
%N Number triangle T(n,k)=(2n)!/(2k)!.
%C Row sums are A051396(n+1). Diagonal sums are A119829. Inverse is the bi-diagonal array A119830. E.g.f. cosh(x*y)/(1-y*x^2) produces an aerated version.
%F Number triangle T(n,k)=[k<=n](2n)!/(2k)!
%e Triangle begins
%e 1,
%e 2, 1,
%e 24, 12, 1,
%e 720, 360, 30, 1,
%e 40320, 20160, 1680, 56, 1,
%e 3628800, 1814400, 151200, 5040, 90, 1
%K easy,nonn,tabl
%O 0,2
%A _Paul Barry_, May 25 2006
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