a(n) = Sum_{k=0..n} C(n,k) * (2^k + 3^k)^k.A251671a(n) = Sum_{k=0..n} C(n,k) * (2^k + 3^k)^k.Terms a(0) =1a(1) =6a(2) =180a(3) =43398a(4) =88701816External referencesoeis: A251671