a(n) = 7*n + 6.

Terms

a(0) =6a(1) =13a(2) =20a(3) =27a(4) =34a(5) =41a(6) =48a(7) =55a(8) =62a(9) =69a(10) =76a(11) =83a(12) =90a(13) =97a(14) =104a(15) =111a(16) =118a(17) =125a(18) =132a(19) =139a(20) =146a(21) =153a(22) =160a(23) =167a(24) =174a(25) =181a(26) =188a(27) =195a(28) =202a(29) =209