1947355domain: NAppears in sequencesExpansion of (x^2-x-1)*(x^3-x^2+x-2) / ((x-1)*(2*x-1)*(x^2+x+1)*(x^2+1)).at n=20A109784Decimal representation of the middle column of the "Rule 109" elementary cellular automaton starting with a single ON (black) cell.at n=20A267210