Number of permutations of 1..n with all differences of elements separated by distances 1 through 4 being respectively unique.
A170810
Number of permutations of 1..n with all differences of elements separated by distances 1 through 4 being respectively unique.
Terms
- a(0) =1a(1) =2a(2) =4a(3) =12a(4) =40a(5) =116a(6) =200a(7) =444a(8) =760a(9) =2160a(10) =4872a(11) =11932a(12) =29252a(13) =71708a(14) =191356a(15) =536908a(16) =1607592a(17) =5184252a(18) =17331516a(19) =61597568a(20) =228854684a(21) =891958912
External references
- oeis: A170810