a(n) = Sum_{k=0..n-1} T(n,k) * T(n,k+1), with T given by A026692.
A026992
a(n) = Sum_{k=0..n-1} T(n,k) * T(n,k+1), with T given by A026692.
Terms
- a(0) =1a(1) =4a(2) =15a(3) =72a(4) =385a(5) =1740a(6) =7200a(7) =33892a(8) =174369a(9) =806288a(10) =3477513a(11) =16493280a(12) =84033826a(13) =393038584a(14) =1732173866a(15) =8260858904a(16) =41899043017a(17) =197360311690a(18) =881681864213
External references
- oeis: A026992