a(n) = 7*2^n + 3.

Terms

a(0) =10a(1) =17a(2) =31a(3) =59a(4) =115a(5) =227a(6) =451a(7) =899a(8) =1795a(9) =3587a(10) =7171a(11) =14339a(12) =28675a(13) =57347a(14) =114691a(15) =229379a(16) =458755a(17) =917507a(18) =1835011a(19) =3670019a(20) =7340035a(21) =14680067a(22) =29360131a(23) =58720259a(24) =117440515a(25) =234881027a(26) =469762051a(27) =939524099a(28) =1879048195a(29) =3758096387