Hi, I was in touch with Mathematica development team and they indicated that currently Mathematica is not capable to determine whether
Sum[Binomial[n - 1, n - i] Sum[Binomial[k + i, i] Binomial[n - 1, n - k], {k, 0, n}], {i, 0, n}] = ? (-1)^n*((-4*n^2 - 16*n - 28)*JacobiP[-1 + n, -1 - 2*n, 2, -1/2] + JacobiP[-2 + n, -2*n, 3, -1/2]*(3 + n)*(-1 + n))*4^n/(48*(1 + n)*n) Could you check whether Sage has such capability? Thanks, Best regards, Alexander R. Povolotsky -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-support+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sage-support/CAMUBbcOZj1gmsH_M%2B9rbmK%3DAUzYad-8j%2BpnwOF6%2BJKjfa14Fkg%40mail.gmail.com.