Test for n = 1, 52 - 1 = 24 which is divisible by 6.
Assume true for some n = k.
ie. 52k - 1 = 6M (where M is some unknown positive integer)
Need to prove true for n = k+1
52(k+1) - 1
= 52k+2 - 1
= 52k.52 - 1
= (6M + 1).25 - 1 (since 52k - 1 = 6M, hence 52k = 6M + 1)
= 25.6M + 25...