Sum_{k=0..n} ((binomial(3*k,k)*binomial(2*n-k,n))/(2*k+1)).
A270489
Sum_{k=0..n} ((binomial(3*k,k)*binomial(2*n-k,n))/(2*k+1)).
Terms
- a(0) =1a(1) =3a(2) =12a(3) =54a(4) =265a(5) =1401a(6) =7903a(7) =47088a(8) =293319a(9) =1892440a(10) =12548041a(11) =84988566a(12) =585314652a(13) =4085026386a(14) =28820064810a(15) =205156454376
External references
- oeis: A270489