Number of permutations of [n] having exactly three adjacent 2-cycles.
A370529
Number of permutations of [n] having exactly three adjacent 2-cycles.
Terms
- a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =1a(7) =4a(8) =16a(9) =100a(10) =730a(11) =5940a(12) =54160a(13) =547540a(14) =6077155a(15) =73473400a(16) =961231264a(17) =13530711096a(18) =203921897844
External references
- oeis: A370529