9623140

Appears in sequences

• Number of distributive lattices; also number of paths with n turns when light is reflected from 4 glass plates.at n=15A006357
• Top line of 4-wave sequence A038197, also bisection of A006357.at n=8A038225
• First row sum of the 4 X 4 matrix M^n, where M={{10, 9, 7, 4}, {9, 8, 6, 3}, {7, 6, 4, 2}, {4, 3, 2, 1}}.at n=5A122186
• Expansion of x - 1/(x - 1/(x - 1/(x - 1/(x + 1)))).at n=15A373568