4824613domain: NAppears in sequencesCyclotomic polynomials at x=13.at n=18A019331Cyclotomic polynomials at x=-13.at n=9A020512a(n) = n^6 - n^3 + 1.at n=13A060891a(n) = sigma_6(n^2)/sigma_3(n^2).at n=12A084220