381551

Appears in sequences

• Number of bargraphs of semiperimeter n having no horizontal segments of length 1 (n>=2). By a horizontal segment of length 1 we mean a horizontal step that is not adjacent to any other horizontal step.at n=18A274493
• a(n) = floor(2^n/(-1 + cot(1/n))).at n=22A332431
• Number of non-isomorphic directed graphs reachable in n steps (and no fewer) by at least 2*n agents using the ANY protocol (see A318154).at n=9A383389