>935, >947

>948 に
 (l+n+k)!/(n+k)! = Π[p=0,l-1] (p+n+k+1),
 k!/(l+k)! = Π[p=0,l-1] 1/(p+k+1),
 (l+m+k)!/(m+k)! = Π[q=0,l-1] (q+m+k+1),
 k!/(l+k)! = Π[q=0,l-1] 1/(q+k+1),
を代入すると いづれもl項の積の形になり
 det(A) = Π[p=0,l-1] {(p+m+n)!/(p+n)!} * {p!/(p+m)!},
 det(B) = Π[q=0,l-1] {(q+m+n)!/(q+m)!} * {q!/(q+n)!},
だから、
 det(A) = det(B).