Final decimal digit of 2^n.

Terms

a(0) =1a(1) =2a(2) =4a(3) =8a(4) =6a(5) =2a(6) =4a(7) =8a(8) =6a(9) =2a(10) =4a(11) =8a(12) =6a(13) =2a(14) =4a(15) =8a(16) =6a(17) =2a(18) =4a(19) =8a(20) =6a(21) =2a(22) =4a(23) =8a(24) =6a(25) =2a(26) =4a(27) =8a(28) =6a(29) =2