778687domain: NAppears in sequencesa(n) is least k such that k and 7k are anagrams in base n (written in base 10).at n=6A023099a(n) = a(1) + a(2) + ... + a(n-1) - a(m) for n >= 4, where m = 2*n - 3 - 2^(p+1) and p is the unique integer such that 2^p < n-1 <= 2^(p+1), with a(1) = 1, a(2) = 3, and a(3) = 2.at n=21A049920