Number of permutations of {1,2,...,n} having equal numbers of 1-cycles and 2-cycles.

A335827

Number of permutations of {1,2,...,n} having equal numbers of 1-cycles and 2-cycles.

Terms

    a(0) =1a(1) =0a(2) =0a(3) =5a(4) =6a(5) =24a(6) =325a(7) =1770a(8) =13020a(9) =130004a(10) =1276956a(11) =13855500a(12) =167506735a(13) =2177721480a(14) =30454243716a(15) =456940935269

External references