41907domain: NAppears in sequencesNumber of ways 1/n can be expressed as the sum of four distinct unit fractions: 1/n = 1/w + 1/x + 1/y + 1/z satisfying 0 < w < x < y < z.at n=45A241883Numbers k for which rank of the elliptic curve y^2=x^3-k*x is 4.at n=29A309034G.f. A(x) satisfies A(x) = 1 + x/(1+x^3) * A(x)^3.at n=8A390171