In #9623, lots of interacts were added to the library. Unfortunately, one (based on this wiki page by Pablo Angulo and Eviatar Bach) was "optimized" a bit too much. We need to replace

        for k in range(N-j, N+j+1):

by

 for k in range(0,2*N):

as in the original.

One can test this by making sure the outputs are the same as at the MathWorld site for this. Thanks to jhpalmieri for discovering this in unrelated testing at #9623.

CC: @jhpalmieri

Component: interact

Keywords: sd41

Author: John Palmieri

Reviewer: Karl-Dieter Crisman

Merged: sage-5.1.beta6

Issue created by migration from https://trac.sagemath.org/ticket/11871