a(n) = (5*n+1) * (6*n+1)^(n-2) * 7^n.A251697a(n) = (5*n+1) * (6*n+1)^(n-2) * 7^n.Terms a(0) =1a(1) =6a(2) =539a(3) =104272a(4) =31513125a(5) =13018130762External referencesoeis: A251697