14286908domain: NAppears in sequencesNumber of distinct solutions of sum{i=1..5}(x(2i-1)*x(2i)) = 0 (mod n), with x() only in 1..n-1.at n=15A180776Number of 2n-bead necklaces labeled with numbers 1..4 allowing reversal, with neighbors differing by exactly 1.at n=20A208667