Number of permutations of 1..n with i-8<=p(i)<=i+5.

Terms

a(0) =1a(1) =2a(2) =6a(3) =24a(4) =120a(5) =720a(6) =4320a(7) =25920a(8) =155520a(9) =858120a(10) =4498296a(11) =23026074a(12) =117437746a(13) =604907611a(14) =3173843821a(15) =16812885360a(16) =89389649752a(17) =475278119520