362231domain: NAppears in sequencesNumbers n such that sopf(n) = sopf(n-1) + sopf(n-2) + sopf(n-3), where sopf(x) = sum of the distinct prime factors of x.at n=4A075784Semiprimes that are (perimeter^2 - hypotenuse^2) of a Pythagorean triple.at n=13A389589