70521domain: NAppears in sequencesNumber of rooted trees with n nodes and 4 leaves.at n=18A055279Numbers k with property that 19*k + {2,4,8,10} are two pairs of consecutive twin primes.at n=14A152926a(n) = Sum_{1 <= x_1, x_2, x_3 <= n} gcd(x_1, x_2, n)/gcd(x_1, x_2, x_3, n).at n=40A373061