# So = 2

S1 = 5

Sn = - Sn - 1 + nSn - 2, n >_ 2

How do I interpret the value of n? Is this number equivalent to S1, S0, or 2? I have tried each option; finding S3 is difficult because I don't know what value to multiply Sn-2 with, when solving for S2. Your assistance would be very helpful:)