-8140625domain: ZAppears in sequencesExpansion of ((1+x)^3 - x^3)/((1+x)^5 - x^5).at n=25A105369a(n) = Sum_{k >= 0}(-1)^k*binomial(n,5*k).at n=27A289306a(n) = Sum_{k >= 0}(-1)^k*binomial(n,5*k+1).at n=28A289321