539041domain: NAppears in sequencesa(n) = (Sum_{k=1..A047380(n)} k^6) / (Sum_{k=1..A047380(n)} k^2).at n=19A133180a(n) = 373 + 1947*n + 3780*n^2 + 3234*n^3 + 1029*n^4.at n=4A134161