99352domain: NAppears in sequencesa(1) = 1; a(2) = 2; thereafter a(n) is the smallest number > a(n-1) which is neither of the form 2*a(i) nor Sum_{j=1..n-1} ( b_j*a(j) ) where 0 < i < n, b_j = 1 or 0.at n=20A331809