a(n) = Sum_{k=0..2n-1} T(n,k) * T(n,k+1), with T given by A027113.
A027141
a(n) = Sum_{k=0..2n-1} T(n,k) * T(n,k+1), with T given by A027113.
Terms
- a(0) =3a(1) =23a(2) =165a(3) =1218a(4) =9247a(5) =71688a(6) =564759a(7) =4506005a(8) =36324407a(9) =295341956a(10) =2418783687a(11) =19932773439a(12) =165151576215
External references
- oeis: A027141