199738domain: NAppears in sequencesNumber of subsets of {1,2,3,...,n} that sum to 0 mod 21.at n=22A068042Decimal representation of the diagonal from the corner to the origin of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 249", based on the 5-celled von Neumann neighborhood.at n=38A287139