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={1,2}.

A080003

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={1,2}.

Terms

    a(0) =1a(1) =1a(2) =1a(3) =1a(4) =4a(5) =8a(6) =13a(7) =22a(8) =40a(9) =77a(10) =140a(11) =252a(12) =456a(13) =834a(14) =1525a(15) =2775a(16) =5049a(17) =9195a(18) =16760a(19) =30536a(20) =55617a(21) =101304a(22) =184544a(23) =336193a(24) =612424a(25) =1115600a(26) =2032216a(27) =3702000a(28) =6743761a(29) =12284729

External references