a(n) = (A268924(n)^2 + 2)/3^n, n >= 0.

Terms

a(0) =2a(1) =1a(2) =2a(3) =18a(4) =6a(5) =2a(6) =354a(7) =118a(8) =1107a(9) =369a(10) =123a(11) =41a(12) =239803a(13) =495074a(14) =3475362a(15) =1158454a(16) =7887171a(17) =2629057a(18) =56207062a(19) =246253281a(20) =82084427a(21) =5389722857a(22) =25755119139a(23) =8585039713a(24) =53195580742a(25) =193589999521