a(n) = 6*a(n-1) - 8*a(n-2) + 2 for n > 1; a(0) = 1, a(1) = 8.

Terms

a(0) =1a(1) =8a(2) =42a(3) =190a(4) =806a(5) =3318a(6) =13462a(7) =54230a(8) =217686a(9) =872278a(10) =3492182a(11) =13974870a(12) =55911766a(13) =223671638a(14) =894735702a(15) =3579041110a(16) =14316361046a(17) =57265837398a(18) =229064136022a(19) =916258116950