a(0)=1, for n>0: a(n) = 4*9^(n-1) - (1/2)*Sum_{i=1..n-1} a(i)*a(n-i).
A085363
a(0)=1, for n>0: a(n) = 4*9^(n-1) - (1/2)*Sum_{i=1..n-1} a(i)*a(n-i).
Terms
- a(0) =1a(1) =4a(2) =28a(3) =212a(4) =1676a(5) =13604a(6) =112380a(7) =940020a(8) =7936620a(9) =67494980a(10) =577309148a(11) =4961187092a(12) =42801458764a(13) =370478720356
External references
- oeis: A085363