Number of connected, loopless 2-regular digraphs, no multiedges, on n nodes.

A307155

Number of connected, loopless 2-regular digraphs, no multiedges, on n nodes.

Terms

    a(0) =1a(1) =0a(2) =0a(3) =1a(4) =2a(5) =5a(6) =22a(7) =90a(8) =616a(9) =4988a(10) =46883a(11) =493406a(12) =5712809a(13) =71909602

External references