Number of self-inverse permutations p on [n] with displacement of elements restricted by 4: |p(i)-i| <= 4.
A239076
Number of self-inverse permutations p on [n] with displacement of elements restricted by 4: |p(i)-i| <= 4.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =4a(4) =10a(5) =26a(6) =66a(7) =158a(8) =376a(9) =891a(10) =2137a(11) =5140a(12) =12376a(13) =29756a(14) =71468a(15) =171596a(16) =412084a(17) =989800a(18) =2377717a(19) =5711705a(20) =13720054a(21) =32955996a(22) =79161006a(23) =190147558a(24) =456743814a(25) =1097123162a(26) =2635347280a(27) =6330234855a(28) =15205529809a(29) =36524416280
External references
- oeis: A239076