22360679774domain: NAppears in sequencesNumber of leg-hypotenuse twin Pythagorean triples < 10^n.at n=20A101904Integer part of Lorentz gamma factor = 1/sqrt(1 - (beta)^2) for beta = 0.9999...(with 9 appearing n times) = 1 - 10^(-n).at n=20A109999