a(n) = Sum_{k=0..[n/2]} 2^(n-2*k-1)*C(n-1,2*k)*C(2*k,k)/(k+1)*a(k), with a(0)=1.
A118929
a(n) = Sum_{k=0..[n/2]} 2^(n-2*k-1)*C(n-1,2*k)*C(2*k,k)/(k+1)*a(k), with a(0)=1.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =5a(4) =14a(5) =44a(6) =152a(7) =569a(8) =2270a(9) =9524a(10) =41576a(11) =187432a(12) =868144a(13) =4117216a(14) =19945408a(15) =98523013a(16) =495521686a(17) =2534420852a(18) =13167361256a(19) =69417635240a(20) =370991119792
External references
- oeis: A118929