a(n) = 7*2^n.

Terms

a(0) =7a(1) =14a(2) =28a(3) =56a(4) =112a(5) =224a(6) =448a(7) =896a(8) =1792a(9) =3584a(10) =7168a(11) =14336a(12) =28672a(13) =57344a(14) =114688a(15) =229376a(16) =458752a(17) =917504a(18) =1835008a(19) =3670016a(20) =7340032a(21) =14680064a(22) =29360128a(23) =58720256a(24) =117440512a(25) =234881024a(26) =469762048a(27) =939524096a(28) =1879048192a(29) =3758096384