a(n) = Sum_{i+j+k=n, 0<=i<=j<=k<=n} (n+2k)!/(i! * j! * (3*k)!).
A092468
a(n) = Sum_{i+j+k=n, 0<=i<=j<=k<=n} (n+2k)!/(i! * j! * (3*k)!).
Terms
- a(0) =1a(1) =1a(2) =3a(3) =24a(4) =71a(5) =366a(6) =2142a(7) =8128a(8) =40063a(9) =223182a(10) =919600a(11) =4477496a(12) =24423998a(13) =104469379a(14) =508145588a(15) =2726623094a(16) =11936904927a(17) =58101760966a(18) =307770506832
External references
- oeis: A092468