10242581819domain: NAppears in sequencesNumber of base 7 circular n-digit numbers with adjacent digits differing by 1 or less.at n=22A124700a(n) = (u+1)^n + (-s-1)^n + (t+1)^n + (-1)^n + (-t+1)^n + (s-1)^n + (-u+1)^n where s = sqrt(2), t = sqrt(2-s), u = sqrt(2+s).at n=22A215503