94118013006domain: NAppears in sequencesa(n) = 3^n - 3*2^n + 3.at n=23A001117Number of primitive (aperiodic) words of length n which contain exactly three different symbols.at n=22A056268A(k,3) where A(k,n) = Sum_{m=1..k} (-1)^(m+1) *binomial(n,m)*m^k.at n=22A179483