Number of permutations p of [n] with no fixed points and cyclic displacement of elements restricted by two: p(i)<>i and (i-p(i) mod n <= 2 or p(i)-i mod n <= 2).
A260074
Number of permutations p of [n] with no fixed points and cyclic displacement of elements restricted by two: p(i)<>i and (i-p(i) mod n <= 2 or p(i)-i mod n <= 2).
Terms
- a(0) =1a(1) =0a(2) =1a(3) =2a(4) =9a(5) =44a(6) =80a(7) =144a(8) =260a(9) =448a(10) =808a(11) =1456a(12) =2640a(13) =4788a(14) =8744a(15) =16016a(16) =29444a(17) =54268a(18) =100304a(19) =185824a(20) =344996a(21) =641664a(22) =1195400a(23) =2230176a(24) =4165904a(25) =7790244a(26) =14581640a(27) =27316240a(28) =51209124a(29) =96060300
External references
- oeis: A260074