a(n) = 1 + 3 * Sum_{k=0..n-1} a(k) * a(n-k-1).
A337167
a(n) = 1 + 3 * Sum_{k=0..n-1} a(k) * a(n-k-1).
Terms
- a(0) =1a(1) =4a(2) =25a(3) =199a(4) =1795a(5) =17422a(6) =177463a(7) =1870960a(8) =20241403a(9) =223438852a(10) =2506596547a(11) =28494103183a(12) =327507800725
External references
- oeis: A337167