a(n) = Sum_{m=0..n} (Sum_{k=0..m} binomial(n,k))^3 = (n+2)*2^(3*n-1) - 3*2^(n-2)*n*binomial(2*n,n).
A007403
a(n) = Sum_{m=0..n} (Sum_{k=0..m} binomial(n,k))^3 = (n+2)*2^(3*n-1) - 3*2^(n-2)*n*binomial(2*n,n).
Terms
- a(0) =1a(1) =9a(2) =92a(3) =920a(4) =8928a(5) =84448a(6) =782464a(7) =7130880a(8) =64117760a(9) =570166784a(10) =5023524864a(11) =43915595776a(12) =381350330368
External references
- oeis: A007403