60466170domain: NAppears in sequencesNumber of primitive (aperiodic) palindromes using a maximum of six different symbols.at n=18A056462Number of primitive (period n) periodic palindromes using a maximum of six different symbols.at n=18A056497a(n) = 6^n - 6.at n=9A178672a(n) = n^10 - n.at n=6A196291