a(n) = Sum_{k = 0..n-1} (-1)^(n+k+1)*binomial(3*n, k)^3.
A375180
a(n) = Sum_{k = 0..n-1} (-1)^(n+k+1)*binomial(3*n, k)^3.
Terms
- a(0) =0a(1) =1a(2) =215a(3) =45928a(4) =10362231a(5) =2450260001a(6) =600869373182
External references
- oeis: A375180
A375180
a(n) = Sum_{k = 0..n-1} (-1)^(n+k+1)*binomial(3*n, k)^3.