a(0) = a(1) = a(2) = 1; a(n) = (1/2) * Sum_{k=0..n-2} binomial(n-2,k) * a(k) * a(n-k-2).
A336023
a(0) = a(1) = a(2) = 1; a(n) = (1/2) * Sum_{k=0..n-2} binomial(n-2,k) * a(k) * a(n-k-2).
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =2a(5) =4a(6) =9a(7) =24a(8) =73a(9) =241a(10) =881a(11) =3526a(12) =15252a(13) =70989a(14) =354454a(15) =1887349a(16) =10674773a(17) =63936181a(18) =404240736a(19) =2690174976a(20) =18798077227a(21) =137612318374
External references
- oeis: A336023