a(n) = (12*n + 8)^2.

Terms

a(0) =64a(1) =400a(2) =1024a(3) =1936a(4) =3136a(5) =4624a(6) =6400a(7) =8464a(8) =10816a(9) =13456a(10) =16384a(11) =19600a(12) =23104a(13) =26896a(14) =30976a(15) =35344a(16) =40000a(17) =44944a(18) =50176a(19) =55696a(20) =61504a(21) =67600a(22) =73984a(23) =80656a(24) =87616a(25) =94864a(26) =102400a(27) =110224a(28) =118336a(29) =126736