28874200domain: NAppears in sequencesNumbers n such that n = Sum_{j>=1} c(j) where c(0) = n, c(j) = floor(c(j-1)/10^k)*(c(j-1) mod 10^k) for j>0, and k is half the number of digits of n, rounded up if the number of digits of n is odd.at n=20A258584