15313310208domain: NAppears in sequencesNumber of permutations of 2 indistinguishable copies of 1..n arranged in a circle with exactly 4 local maxima.at n=7A159718Triangle read by rows: T(n,k) is the number of permutations of 2 indistinguishable copies of 1..n arranged in a circle with exactly k local maxima.at n=40A334778