418613domain: NAppears in sequencesHypotenuse C of primitive Pythagorean triangles such that perimeters are Averages of twin prime pairs, q=p+1, a=q^2-p^2, c=q^2+p^2, b=2*p*q, s=a+b+c, s-+1 are primes.at n=27A155175Numbers k such that all of k, k+1 and k+2 are the sums of consecutive squares.at n=16A368590