a(n) = (12*n + 4)^2.

Terms

a(0) =16a(1) =256a(2) =784a(3) =1600a(4) =2704a(5) =4096a(6) =5776a(7) =7744a(8) =10000a(9) =12544a(10) =15376a(11) =18496a(12) =21904a(13) =25600a(14) =29584a(15) =33856a(16) =38416a(17) =43264a(18) =48400a(19) =53824a(20) =59536a(21) =65536a(22) =71824a(23) =78400a(24) =85264a(25) =92416a(26) =99856a(27) =107584a(28) =115600a(29) =123904