a(n) = ((7 + sqrt(7))^n + (7 - sqrt(7))^n)/2.

A145302

a(n) = ((7 + sqrt(7))^n + (7 - sqrt(7))^n)/2.

Terms

    a(0) =1a(1) =7a(2) =56a(3) =490a(4) =4508a(5) =42532a(6) =406112a(7) =3899224a(8) =37532432a(9) =361686640a(10) =3487250816a(11) =33630672544a(12) =324364881344

External references