a(n) = Sum_{k=0..floor(n/2)-1} T(n,k) * T(n,k+2), with T given by A026009.
A027289
a(n) = Sum_{k=0..floor(n/2)-1} T(n,k) * T(n,k+2), with T given by A026009.
Terms
- a(0) =1a(1) =3a(2) =18a(3) =55a(4) =264a(5) =847a(6) =3744a(7) =12465a(8) =52868a(9) =180895a(10) =749220a(11) =2617173a(12) =10680656a(13) =37915317a(14) =153240864a(15) =551019963a(16) =2212417314a(17) =8038946075a(18) =32129224712a(19) =117758845827a(20) =469105048654
External references
- oeis: A027289