Jacobsthal numbers A001045 incremented by 2.

Terms

a(0) =2a(1) =3a(2) =3a(3) =5a(4) =7a(5) =13a(6) =23a(7) =45a(8) =87a(9) =173a(10) =343a(11) =685a(12) =1367a(13) =2733a(14) =5463a(15) =10925a(16) =21847a(17) =43693a(18) =87383a(19) =174765a(20) =349527a(21) =699053a(22) =1398103a(23) =2796205a(24) =5592407a(25) =11184813a(26) =22369623a(27) =44739245a(28) =89478487a(29) =178956973