85451020204domain: NAppears in sequencesExpansion of 1/((1-x^2)*(1-4*x+x^2)).at n=19A072335Coefficients of the series giving the best rational approximations to sqrt(3).at n=9A123480Numbers n such that the sum of the pentagonal numbers P(n) and P(n+1) is equal to the sum of the hexagonal numbers H(m) and H(m+1) for some m.at n=4A251991