189501

Appears in sequences

• Numbers k such that sigma(k) = phi(k+1) + phi(k) + phi(k-1).at n=28A065986
• The number of ways that a straight line segment of length n, marked into n equal units, can be surrounded in a plane by one layer of regular polygons of unit edge that fit together without any gaps or overlaps, such that every polygon shares either a vertex or an exact unit edge with the segment. ("Line wreaths of length n.") Ways that differ by reflection or rotation are not counted as different.at n=10A158091
• Breadth-first traversal of a binary tree in which the value at the n-th node is equal to ParentNode()*prime(n-1).at n=30A268878