a(n) = Product_{k=0..n} (3^k + 5^(n-k)).A369678a(n) = Product_{k=0..n} (3^k + 5^(n-k)).Terms a(0) =2a(1) =24a(2) =2080a(3) =1382976a(4) =7148699648External referencesoeis: A369678