206671502025domain: NAppears in sequencesDenominators of continued fraction convergents to sqrt(168).at n=17A041311Denominators of continued fraction convergents to sqrt(672).at n=17A042293Chebyshev polynomials of the second kind, U(n,x), evaluated at x=13.at n=9A097309256*n^8 - 448*n^6 + 240*n^4 - 40*n^2 + 1.at n=13A242853