Confluent Heun function

Does the confluent Heun function exist in Mathematica?

I try to evaluate the following,

DSolve[(1 - 2*M/r)^2*R''[r] + (1 - 2*M/r)*2*M/r^2*
R'[r] + (c^2 + 2*M*m^2/r)*R[r] == 0, R[r], r, Assumptions -> {m > 0, M > 0, c > 0}] 

but there are no results. Also, using Maple, my friend show that the solutions is confluent Heun function. Can anybody help me to understand what I do wrong?