139997

Appears in sequences

• Number of distributive lattices; also number of paths with n turns when light is reflected from 4 glass plates.at n=11A006357
• 4-wave sequence.at n=36A038197
• Top line of 4-wave sequence A038197, also bisection of A006357.at n=6A038225
• Let i be in {1,2,3,4} and let r >= 0 be an integer. Let p = {p_1, p_2, p_3, p_4} = {-1,0,1,2}, n=3*r+p_i, and define a(-1)=1. Then a(n)=a(3*r+p_i) gives the quantity of H_(9,1,0) tiles in a subdivided H_(9,i,r) tile after linear scaling by the factor Q^r, where Q=sqrt(x^3-2*x) with x=2*cos(Pi/9).at n=41A187503
• Let i be in {1,2,3,4} and let r >= 0 be an integer. Let p = {p_1, p_2, p_3, p_4} = {-1,0,1,2}, n=3*r+p_i, and define a(-1)=0. Then a(n)=a(3*r+p_i) gives the quantity of H_(9,4,0) tiles in a subdivided H_(9,i,r) tile after linear scaling by the factor Q^r, where Q=sqrt(x^3-2*x) with x=2*cos(Pi/9).at n=38A187506
• Number of ways to split an n-cycle into connected subgraphs, all having at least three vertices.at n=31A323951
• Expansion of x - 1/(x - 1/(x - 1/(x - 1/(x + 1)))).at n=11A373568