102760448domain: NAppears in sequencesGeneralized Euler phi function (for p=2).at n=27A003473a(0)=1, a(1)=6, a(n)=49*8^(n-2) if n>=2.at n=9A055847Number of functions f:[n]->[n] such that f[(2*x) mod n]=[2*f(x)] mod n for all x in [n], for n=1,2,3,... Here [n] denotes {0,1,2,...,n-1}.at n=27A117987a(n) = n^2*8^n.at n=7A128787