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T. Amdeberhan
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Extending the discussion on "super Catalan" numbers

Ira Gessel "dubbed" the name super Catalan to $$S(m,n)=\frac{(2m)!(2n)!}{m!n!(m+n)!}$$ and offers a combinatorial proof in his paper

http://people.brandeis.edu/~gessel/homepage/papers/superballot.pdf

Note. The numbers $\frac12S(m,n)$ are also integers.

I would like to extend the discussion by asking for a proof that the following numbers, which I call super super Catalan numbers type 1, are integers $$S(x,y,z)=\frac13\frac{(3x)!(3y)!(3z)!}{x!^2y!^2z!^2(x+y+z)!}$$ and the same question of integrality about the numbers, which I call super super Catalan numbers of type 2, $$T(x,y,z)=\frac{x}3\frac{(3x)!(3y)!(3z)!}{x!^3y!^3z!^3(x+y+z)}$$ provided that $x, y, z$ are non-negative integers.

I don't have a proof to these claims, but I am convinced of their truth. Even a generating function method is acceptable, yet a combinatorial proof is much desirable.

T. Amdeberhan
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