161766061domain: NAppears in sequencesNumber of walks of length n between two nodes at distance 2 in the cycle graph C_7.at n=28A095307a(n) = Sum_{k=0..floor(n/7)} binomial(n,7*k).at n=30A306852a(n) = Sum_{k=0..n} binomial(2*n,7*k).at n=15A387845