31998

Appears in sequences

• Number of distributive lattices; also number of paths with n turns when light is reflected from 8 glass plates.at n=6A030112
• a(n) = (n+1)*(n+2)*(61*n^4 + 366*n^3 + 845*n^2 + 888*n + 360)/720.at n=7A108675
• Numbers k such that the first 9 digits of the k-th Lucas number are 1-9 pandigital.at n=9A216489
• Triangle T(n,k) (n >= 1 and 1 <= k <= n) read by rows, arising from the Mosaic Problem.at n=5A364440