229755926568domain: NAppears in sequencesDenominators of continued fraction convergents to sqrt(440).at n=15A041839128*n^7-192*n^5+80*n^3-8*n.at n=21A242852a(n) = U(n, 3*n), where U(n, x) is the Chebyshev polynomial of the second kind.at n=7A349076