Number of distributive lattices; also number of paths with n turns when light is reflected from 5 glass plates.

A006358

Number of distributive lattices; also number of paths with n turns when light is reflected from 5 glass plates.

Terms

    a(0) =1a(1) =5a(2) =15a(3) =55a(4) =190a(5) =671a(6) =2353a(7) =8272a(8) =29056a(9) =102091a(10) =358671a(11) =1260143a(12) =4427294a(13) =15554592a(14) =54648506a(15) =191998646a(16) =674555937a(17) =2369942427a(18) =8326406594a(19) =29253473175a(20) =102777312308a(21) =361091343583

External references