20265640domain: NAppears in sequencesNumber of arrangements of n+2 nonzero numbers x(i) in -4..4 with the sum of x(i)*x(i+1) equal to zero.at n=7A188244Number of arrangements of 10 nonzero numbers x(i) in -n..n with the sum of x(i)*x(i+1) equal to zero.at n=3A188256