a(n) = Sum_{i+j+k=n, 0<=i<=n, 0<=j<=n, 0<=k<=n} (n+i+j)!/((i+j)! * j! * k!).
A092471
a(n) = Sum_{i+j+k=n, 0<=i<=n, 0<=j<=n, 0<=k<=n} (n+i+j)!/((i+j)! * j! * k!).
Terms
- a(0) =1a(1) =5a(2) =43a(3) =495a(4) =7281a(5) =133173a(6) =2945755a(7) =76769759a(8) =2306295265a(9) =78492222693
External references
- oeis: A092471