a(n) = 2*prime(n) - 2.

Terms

a(0) =2a(1) =4a(2) =8a(3) =12a(4) =20a(5) =24a(6) =32a(7) =36a(8) =44a(9) =56a(10) =60a(11) =72a(12) =80a(13) =84a(14) =92a(15) =104a(16) =116a(17) =120a(18) =132a(19) =140a(20) =144a(21) =156a(22) =164a(23) =176a(24) =192a(25) =200a(26) =204a(27) =212a(28) =216a(29) =224