12053081880domain: NAppears in sequencesNumber of n X 2 0..2 arrays with some element plus some horizontally or vertically adjacent neighbor totalling two exactly once.at n=17A268633a(n) = (n + 1)^(n - 1) * lcm{k + 1 : 0 <= k <= n}. Main diagonal of triangle A362995.at n=8A362992