Number of permutations of 1..n with all differences of elements separated by distances 1 or 2 being respectively unique.
A170808
Number of permutations of 1..n with all differences of elements separated by distances 1 or 2 being respectively unique.
Terms
- a(0) =1a(1) =2a(2) =4a(3) =12a(4) =40a(5) =116a(6) =252a(7) =768a(8) =2704a(9) =12756a(10) =63168a(11) =338308a(12) =1956876a(13) =11971780a(14) =77909884a(15) =535178056a(16) =3906154920a(17) =30146769464a(18) =244980749052
External references
- oeis: A170808