a(n) = 3^(3*n + 1).A013732a(n) = 3^(3*n + 1).Terms a(0) =3a(1) =81a(2) =2187a(3) =59049a(4) =1594323a(5) =43046721a(6) =1162261467a(7) =31381059609a(8) =847288609443External referencesoeis: A013732