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

Terms

a(0) =1a(1) =1a(2) =1a(3) =3a(4) =6a(5) =10a(6) =18a(7) =35a(8) =65a(9) =119a(10) =221a(11) =412a(12) =764a(13) =1416a(14) =2629a(15) =4881a(16) =9057a(17) =16807a(18) =31194a(19) =57894a(20) =107442a(21) =199399a(22) =370065a(23) =686799a(24) =1274617a(25) =2365544a(26) =4390184a(27) =8147680a(28) =15121161a(29) =28063153