6341787648domain: NAppears in sequencesa(1) = 1; a(n) is the smallest multiple of a(n-1) not divisible by 10 which is greater than the digit reversal of a(n-1). In case R(a(n-1)) < a(n-1) then a(n) = 2*a(n-1).at n=25A076086(1/2) times the sum of the elements of all subsets of [n] whose sum is divisible by two.at n=27A309294