298609domain: NAppears in sequencesa(n) = 10*a(n-1) - 23*a(n-2) for n > 1; a(0) = 3, a(1) = 23.at n=6A164536Smallest positive integer which cannot be calculated by an expression containing n binary operators (any of add, subtract, multiply and divide) whose operands are any integer between 1 and 9; parentheses allowed.at n=8A181898