1956242

Appears in sequences

• a(n) = -(u^n-1)*(v^n-1) with u = 2+sqrt(3), v = 2-sqrt(3).at n=10A129743
• Continued fraction expansion for exp( Sum_{n>=1} 1/(n*A003500(n)) ), where A003500(n) = (2+sqrt(3))^n + (2-sqrt(3))^n.at n=21A174500
• Number of perfect matchings in the graph C_4 X C_n.at n=8A220864
• Number of perfect matchings in the graph C_{11} X C_{2n}.at n=0A308761