a(n) = 4*n + 3.

Terms

a(0) =3a(1) =7a(2) =11a(3) =15a(4) =19a(5) =23a(6) =27a(7) =31a(8) =35a(9) =39a(10) =43a(11) =47a(12) =51a(13) =55a(14) =59a(15) =63a(16) =67a(17) =71a(18) =75a(19) =79a(20) =83a(21) =87a(22) =91a(23) =95a(24) =99a(25) =103a(26) =107a(27) =111a(28) =115a(29) =119