DM
2006
14 years 19 days ago
2006
By a very simple argument, we prove that if l, m, n {0, 1, 2, . . . } then l k=0 (-1)m-k l k m - k n 2k k - 2l + m = l k=0 l k 2k n n - l m + n - 3k - l . On the basis of this ide...