a(n) = ((1 + 3*sqrt(2))*(3 + sqrt(2))^n + (1 - 3*sqrt(2))*(3 - sqrt(2))^n)/2.
A163614
a(n) = ((1 + 3*sqrt(2))*(3 + sqrt(2))^n + (1 - 3*sqrt(2))*(3 - sqrt(2))^n)/2.
Terms
- a(0) =1a(1) =9a(2) =47a(3) =219a(4) =985a(5) =4377a(6) =19367a(7) =85563a(8) =377809a(9) =1667913a(10) =7362815a(11) =32501499a(12) =143469289a(13) =633305241a(14) =2795546423a(15) =12340141851a(16) =54472026145a(17) =240451163913
External references
- oeis: A163614