a(n) counts anti-chains of size four in "0,1,2" Motzkin trees on n edges.

A335355

a(n) counts anti-chains of size four in "0,1,2" Motzkin trees on n edges.

Terms

    a(0) =5a(1) =55a(2) =420a(3) =2600a(4) =14175a(5) =70665a(6) =329800a(7) =1462680a(8) =6228945a(9) =25661875a(10) =102847560a(11) =402706500a(12) =1545715325a(13) =5831511195a(14) =21671504880a(15) =79475234200a(16) =288043346370

External references