Number of permutations of 1..n with i-7<=p(i)<=i+6.

Terms

a(0) =1a(1) =2a(2) =6a(3) =24a(4) =120a(5) =720a(6) =5040a(7) =35280a(8) =221040a(9) =1277160a(10) =7021176a(11) =37727898a(12) =202229266a(13) =1096832395a(14) =6077248381a(15) =34068685392a(16) =191920490008