210761domain: NPropertiesPrimalityPrimeyesAppears in sequencesNumbers k such that (7^k - 5^k)/2 is prime.at n=13A128344G.f. 1-(2*x^3)/(-sqrt(-3*x^4-4*x^3-2*x^2+1)-x^2+1).at n=24A247162Prime numbersat n=18872