a(n) = Sum_{i=1..n} Sum_{j=1..n} Sum_{k=1..n} (i+j+k)!/(3!*i!*j!*k!).
A144511
a(n) = Sum_{i=1..n} Sum_{j=1..n} Sum_{k=1..n} (i+j+k)!/(3!*i!*j!*k!).
Terms
- a(0) =0a(1) =1a(2) =37a(3) =842a(4) =18252a(5) =405408a(6) =9268549a(7) =216864652a(8) =5165454442a(9) =124762262630
External references
- oeis: A144511