python3 - <<'EOF' A=[2,3,4,5,7,9,11,13,16,17,19,23,25,29,31,36,37,41,43,47,49] N=21 T={} for i in range(N): for j in range(i+1,N): d=A[j]-A[i] T.setdefault(d*d,[]).append(((1<>1) z=y^p if z: b=(z&-z).bit_length()-1 v=A[b] if y>>b& 1: n+=1 s+=v q+=v*v else: n-=1 s-=v q-=v*v p=y if n>2: u=4*(n*q-s*s) d=n*n if u%d==0 and u//d in T: for pm,i,j in T[u//d]: if y&pm==pm: R.add((i,j)) if R: i,j=min(R) print([A[i],A[j]]) else: print('NONE') EOF