a(n) = Sum_{k=0..n-1} cos(Pi*k/2)*binomial(n-1,k)*a(n-1-k)*a(k) for n > 0, a(0) = 1.
A190904
a(n) = Sum_{k=0..n-1} cos(Pi*k/2)*binomial(n-1,k)*a(n-1-k)*a(k) for n > 0, a(0) = 1.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =0a(4) =-3a(5) =-12a(6) =-27a(7) =0a(8) =441a(9) =3024a(10) =11529a(11) =0a(12) =-442827a(13) =-4390848a(14) =-23444883a(15) =0a(16) =1636819569a(17) =21224560896a(18) =145703137041a(19) =0a(23) =0
External references
- oeis: A190904