a(n) = Sum_{k=0..n} binomial(n+k,n)*binomial(2*n-3,n-k-1) for n>1, a(n) = n for n<=1.
A278689
a(n) = Sum_{k=0..n} binomial(n+k,n)*binomial(2*n-3,n-k-1) for n>1, a(n) = n for n<=1.
Terms
- a(0) =0a(1) =1a(2) =4a(3) =25a(4) =170a(5) =1204a(6) =8736a(7) =64416a(8) =480480a(9) =3615040a(10) =27382784a(11) =208539136a(12) =1595216896a(13) =12247746560a(14) =94330470400a(15) =728474664960
External references
- oeis: A278689