a(n) = 12*n + 4.

Terms

a(0) =4a(1) =16a(2) =28a(3) =40a(4) =52a(5) =64a(6) =76a(7) =88a(8) =100a(9) =112a(10) =124a(11) =136a(12) =148a(13) =160a(14) =172a(15) =184a(16) =196a(17) =208a(18) =220a(19) =232a(20) =244a(21) =256a(22) =268a(23) =280a(24) =292a(25) =304a(26) =316a(27) =328a(28) =340a(29) =352