a(n) = Sum_{k=0..floor(n/2)} binomial(4*n-k,n-2*k).
A371743
a(n) = Sum_{k=0..floor(n/2)} binomial(4*n-k,n-2*k).
Terms
- a(0) =1a(1) =4a(2) =29a(3) =231a(4) =1926a(5) =16491a(6) =143683a(7) =1267395a(8) =11282393a(9) =101151544a(10) =912011633a(11) =8260998772a(12) =75115815749a(13) =685232639419
External references
- oeis: A371743