231113

Appears in sequences

• a(n) = Sum_{1 <= x, y <= n} lcm(x, y).at n=32A064951
• a(n) = (a(n-1) * a(n-3) - (-1)^n * a(n-2)^2) / a(n-4) with a(0) = -3, a(1) = 7, a(2) = 1, a(3) = 46.at n=9A247382