3843360domain: NAppears in sequencesq-factorial numbers for q=-13.at n=4A015028a(n) = Sum_{1 <= x_1 <= x_2 <= x_3 <= x_4 <= x_5 <= x_6 <= n} gcd(x_1, x_2, x_3 , x_4, x_5, x_6, n).at n=34A343520