Number of connected functions on n points with a loop of length 4.

Terms

a(0) =1a(1) =1a(2) =4a(3) =11a(4) =35a(5) =97a(6) =282a(7) =792a(8) =2243a(9) =6275a(10) =17602a(11) =49206a(12) =137713a(13) =385208a(14) =1078667a(15) =3022342a(16) =8478199a(17) =23807190a(18) =66932592a(19) =188394855a(20) =530911452a(21) =1497892857a(22) =4230987944a(23) =11964356354a(24) =33869704270a(25) =95982410945a(26) =272279600817a(27) =773153124315