Number of connected functions on n points with a loop of length 6.

Terms

a(0) =1a(1) =1a(2) =5a(3) =18a(4) =63a(5) =206a(6) =671a(7) =2087a(8) =6434a(9) =19472a(10) =58375a(11) =173316a(12) =511452a(13) =1500697a(14) =4386021a(15) =12775455a(16) =37118209a(17) =107621858a(18) =311552351a(19) =900775893a(20) =2601887149a(21) =7510011727a(22) =21664873773a(23) =62473966631a(24) =180104101037a(25) =519126161517