a(n) = Sum_{k=0..floor(n/2)} binomial(n-k, k-1)*4^(n-k-1)*(5/4)^k.

A099622

a(n) = Sum_{k=0..floor(n/2)} binomial(n-k, k-1)*4^(n-k-1)*(5/4)^k.

Terms

    a(0) =0a(1) =1a(2) =8a(3) =53a(4) =316a(5) =1785a(6) =9744a(7) =51997a(8) =273092a(9) =1417889a(10) =7299160a(11) =37334661a(12) =190028748a(13) =963565513a(14) =4871514656a(15) =24572321645a(16) =123720601684a(17) =622038982257

External references