455026domain: NAppears in sequencesRecursion based on Exp[Pi/4]: a(n)=Floor[a(n-1)*Exp[Pi/4]] Angular domain {0,Pi/4} is the smallest self-similar piece of a sine wave.at n=18A136671Number of length-4 0..n arrays with no repeated value unequal to the previous repeated value plus one mod n+1.at n=24A268945