6472000domain: NAppears in sequencesa(n) = a(1) + a(2) + ... + a(n-1) + a(m) for n >= 3, where m = n - 1 - 2^p and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = a(2) = 1.at n=23A049942