a(n) = Sum_{k=0..2n-1} T(n,k) * T(n,k+1), with T given by A026568.
A027278
a(n) = Sum_{k=0..2n-1} T(n,k) * T(n,k+1), with T given by A026568.
Terms
- a(0) =2a(1) =8a(2) =60a(3) =312a(4) =2030a(5) =11752a(6) =74174a(7) =450292a(8) =2829898a(9) =17572000a(10) =110733420a(11) =695885000a(12) =4403631638a(13) =27874477216a(14) =177101756296
External references
- oeis: A027278