a(n) = Sum_{k=0..floor((n-1)/2)} T(n,k) * T(n,k+2), with T given by A026022.
A027296
a(n) = Sum_{k=0..floor((n-1)/2)} T(n,k) * T(n,k+2), with T given by A026022.
Terms
- a(0) =1a(1) =6a(2) =22a(3) =100a(4) =345a(5) =1470a(6) =5096a(7) =21120a(8) =74175a(9) =302698a(10) =1076922a(11) =4352140a(12) =15660827a(13) =62876490a(14) =228468272a(15) =913093664a(16) =3345466023a(17) =13326904266a(18) =49176362780a(19) =195434713432a(20) =725586231766
External references
- oeis: A027296