Number of distributive lattices; also number of paths with n turns when light is reflected from 7 glass plates.

A025030

Number of distributive lattices; also number of paths with n turns when light is reflected from 7 glass plates.

Terms

    a(0) =1a(1) =7a(2) =28a(3) =140a(4) =658a(5) =3164a(6) =15106a(7) =72302a(8) =345775a(9) =1654092a(10) =7911970a(11) =37846314a(12) =181033035a(13) =865951710a(14) =4142180085a(15) =19813648817a(16) =94776329265a(17) =453351783116

External references