a(n) = (1/30)*A028361(n) for n>=3.A374854a(n) = (1/30)*A028361(n) for n>=3.Terms a(0) =1a(1) =9a(2) =153a(3) =5049a(4) =328185a(5) =42335865a(6) =10880317305External referencesoeis: A374854