Number of directed graphs of 2*n vertices each having an in-degree and out-degree of 1 such that the graph specifies a pairwise connected gift exchange.
A322751
Number of directed graphs of 2*n vertices each having an in-degree and out-degree of 1 such that the graph specifies a pairwise connected gift exchange.
Terms
- a(0) =1a(1) =0a(2) =4a(3) =80a(4) =4704a(5) =436992a(6) =58897920a(7) =10880501760
External references
- oeis: A322751