128511

Appears in sequences

• a(n+2) = 3*a(n) - a(n-2) with a(0) = 1, a(1) = 3, a(2) = 6.at n=19A018186
• Expansion of (1-x^2)/(1-3*x-x^2).at n=10A052906
• List of quadruples (r,s,t,u): the matrix M = [[4,12,9][2,5,3][1,2,1]] is raised to successive powers, then (r,s,t,u) are the square roots of M[3,1], M[3,3], M[1,1], M[1,3] respectively.at n=43A249579