1699831domain: NAppears in sequencesa(n) = T(n,n-3), T given by A026568. Also a(n) = number of integer strings s(0),...,s(n) counted by T, such that s(n)=3.at n=15A026572Number of 7-bead necklaces labeled with numbers -n..n allowing reversal, with sum zero with no three beads in a row equal.at n=8A209348