Number of permutations satisfying -k<=p(i)-i<=r and p(i)-i not in I, i=1..n, with k=2, r=3, I={-1}.

Terms

a(0) =1a(1) =1a(2) =1a(3) =3a(4) =7a(5) =15a(6) =29a(7) =59a(8) =126a(9) =262a(10) =542a(11) =1121a(12) =2328a(13) =4839a(14) =10039a(15) =20827a(16) =43220a(17) =89704a(18) =186172a(19) =386345a(20) =801768a(21) =1663916a(22) =3453137a(23) =7166272a(24) =14872078a(25) =30863935a(26) =64051787a(27) =132926308a(28) =275861116a(29) =572492846