Maxima Function
parGosper (F_{n,k}, k, n, d)
Attempts to find a d-th order recurrence for F_{n,k}.
The algorithm yields a sequence [s_1, s_2, ..., s_m] of solutions. Each solution has the form
[R(n, k), [a_0, a_1, ..., a_d]]
parGosper
returns []
if it fails to find a recurrence.