a(n) = Sum_{k=0..n} binomial(n,k)^(n+k).A206152a(n) = Sum_{k=0..n} binomial(n,k)^(n+k).Terms a(0) =1a(1) =2a(2) =10a(3) =326a(4) =64066a(5) =111968752External referencesoeis: A206152