How do I prove -LSB- math -RSB- n ^ 5-n -LSB- / math -RSB- is divisible by -LSB- math -RSB- 5 -LSB- / math -RSB- ?
Can we prove that -LSB- math -RSB- n ^ 5-5n ^ 3 +4 n -LSB- / math -RSB- is divisible by 20 ?