Number of derangements of a set of n elements where 2 specific elements cannot appear in each other's positions.
A331007
Number of derangements of a set of n elements where 2 specific elements cannot appear in each other's positions.
Terms
- a(0) =1a(1) =0a(2) =0a(3) =0a(4) =4a(5) =24a(6) =168a(7) =1280a(8) =10860a(9) =101976a(10) =1053136a(11) =11881152a(12) =145510740a(13) =1923678680a(14) =27313300344a(15) =414633520704
External references
- oeis: A331007