a(n) = ((3 + 2*sqrt(2))*(3 + sqrt(2))^n + (3 - 2*sqrt(2))*(3 - sqrt(2))^n)/2.
A163606
a(n) = ((3 + 2*sqrt(2))*(3 + sqrt(2))^n + (3 - 2*sqrt(2))*(3 - sqrt(2))^n)/2.
Terms
- a(0) =3a(1) =13a(2) =57a(3) =251a(4) =1107a(5) =4885a(6) =21561a(7) =95171a(8) =420099a(9) =1854397a(10) =8185689a(11) =36133355a(12) =159500307a(13) =704068357a(14) =3107907993a(15) =13718969459a(16) =60558460803a(17) =267317978605
External references
- oeis: A163606