a(n) = Sum_{k=0..n-2} T(n,k) * T(n,k+2), with T given by A026681.
A026988
a(n) = Sum_{k=0..n-2} T(n,k) * T(n,k+2), with T given by A026681.
Terms
- a(0) =1a(1) =10a(2) =69a(3) =340a(4) =1696a(5) =8774a(6) =44500a(7) =203884a(8) =998953a(9) =5026154a(10) =24474925a(11) =110862660a(12) =540493911a(13) =2706193730a(14) =13062307900a(15) =59214077236a(16) =288140818097
External references
- oeis: A026988