3. Permutations with relative forbidden position A Permutations of (1, 2,e., n with relative forbidden position is a permutation in which none of the patterns i, i+l(i=l, 2,.., n)occurs. We denote by Qn the number of the permutations of (1, 2,, n with relative forbidden position Theorem4.16:Forn≥1, Qn=n!-C(n-1,1)(n-1)+C(n-1,2)(n-2)!-…+(-1)m1 C(n-1,n-1)1!▪ 3. Permutations with relative forbidden position ▪ A Permutations of {1,2,…,n} with relative forbidden position is a permutation in which none of the patterns i,i+1(i=1,2,…,n) occurs. We denote by Qn the number of the permutations of {1,2,…,n} with relative forbidden position. ▪ Theorem 4.16：For n1, ▪ Qn=n!-C(n-1,1)(n-1)!+C(n-1,2)(n-2)!-…+(-1)n-1 C(n-1,n-1)1!