76566domain: NAppears in sequencesn times n+4 gives the concatenation of two numbers m and m-6.at n=4A116248Number of vertices in an equilateral triangle "frame" of size n (see Comments in A328526 for definition).at n=20A333031a(n) = Sum_{d|n} d^(n/d) * binomial(n/d,d).at n=20A376016