a(n) = Sum_{i+j+k=n, 0<=i<=j<=k<=n} (n+2j)!/(i! * (3j)! * k!).
A092469
a(n) = Sum_{i+j+k=n, 0<=i<=j<=k<=n} (n+2j)!/(i! * (3j)! * k!).
Terms
- a(0) =1a(1) =1a(2) =13a(3) =91a(4) =1081a(5) =10606a(6) =181189a(7) =2025325a(8) =38378449a(9) =548523856a(10) =10811257051a(11) =176339404099
External references
- oeis: A092469