169772domain: NAppears in sequencesG.f. A(x) satisfies: 1 = ...(((((A(x) - x^2)^(1/2) - x^3)^(1/2) - x^4)^(1/2) - x^5)^(1/2) - x^6)^(1/2) -...- x^n)^(1/2) -..., an infinite series of nested square roots.at n=18A275691Number of unrooted 4-regular one-face maps on genus g surface.at n=3A290937