fails:Array#repeated_combination when no block is given returned Enumerator size returns 0 when the combination_size is < 0
fails:Array#repeated_combination when no block is given returned Enumerator size returns 1 when the combination_size is 0
fails:Array#repeated_combination when no block is given returned Enumerator size returns the binomial coeficient between combination_size and array size + combination_size -1
