a(n) = (A271222(n)^2 + 2)/3^n, n >= 0.

Terms

a(0) =2a(1) =2a(2) =3a(3) =1a(4) =43a(5) =201a(6) =67a(7) =1289a(8) =2278a(9) =14662a(10) =53782a(11) =171798a(12) =57266a(13) =312537a(14) =104179a(15) =7353209a(16) =14081926a(17) =94917254a(18) =148495259a(19) =338541478a(20) =2498895558a(21) =832965186a(22) =277655062a(23) =45869694854a(24) =90480235883a(25) =230874654662