Number of permutations of 1..n with i-8<=p(i)<=i+6.

Terms

a(0) =1a(1) =2a(2) =6a(3) =24a(4) =120a(5) =720a(6) =5040a(7) =35280a(8) =246960a(9) =1573200a(10) =9376680a(11) =53715384a(12) =302432574a(13) =1701740006a(14) =9682617631a(15) =56153444761a(16) =329186004844