43490761domain: NPropertiesPrimalityPrimeyesAppears in sequencesa(0)=1, a(1)=4, a(n) = 10a(n-1) + a(n-2).at n=8A109109Hypotenuses of primitive Pythagorean triples in A195571 and A195572.at n=10A195573Prime numbersat n=2632463