146490domain: NAppears in sequencesCoefficient of x^6 in expansion of (1+x+x^2)^n.at n=17A005714Sum of the next n members of the list of twin primes.at n=23A038345a(n) = n! * Sum_{k=1..n} Sum_{d|k} 1/(d * ((k/d)!)^d).at n=7A356407