Talk:Binomial type

A funny sum
Anyone ever see something that looks like this:


 * $$\sum_{k=0}^n {n \choose k} y^k

\frac {1}{k!} \frac{d^k}{dx^k} f(x)$$

Any identities, relations,etc. for such a thing? Does it have a name? Its painfully suggestive of something but I can't put my finger on it ... linas 04:30, 19 August 2005 (UTC)


 * Those are called Appel sequences. Like sequences of binomial type, they're a special case of Sheffer sequences. Michael Hardy 18:29, 8 May 2006 (UTC)

i dont get it, whats the definition?