438683domain: NAppears in sequencesa(n) = round(n*phi^20), where phi is the golden ratio, A001622.at n=29A004955a(n) = ceiling(n*phi^20), where phi is the golden ratio, A001622.at n=29A004975Number of periodic palindromic structures using a maximum of four different symbols.at n=22A056505a(n) = (A259756(n)-1)/8.at n=28A275417