a(n) = C(n)*(C(n)-1)/2, where C(n) are the Catalan numbers (A000108).
A051789
a(n) = C(n)*(C(n)-1)/2, where C(n) are the Catalan numbers (A000108).
Terms
- a(0) =0a(1) =0a(2) =1a(3) =10a(4) =91a(5) =861a(6) =8646a(7) =91806a(8) =1021735a(9) =11817091a(10) =141044410a(11) =1727867505a(12) =21634392066a(13) =275949833550
External references
- oeis: A051789