Number of ordered pairs of derangements on [n] that commute.
A362820
Number of ordered pairs of derangements on [n] that commute.
Terms
- a(0) =1a(1) =0a(2) =1a(3) =4a(4) =33a(5) =136a(6) =1825a(7) =10956a(8) =163009a(9) =1575568a(10) =23894721a(11) =280090900a(12) =5410068961a(13) =73066199064
External references
- oeis: A362820