4357584144domain: NAppears in sequencesNumber of permutations satisfying -k<=p(i)-i<=r and p(i)-i not in I, i=1..n, with k=3, r=3, I={-2,0,2}.at n=38A079986a(n) = T(n)^2, where T(n) = A000073(n) is the n-th tribonacci number.at n=21A085697