--- id: 5900f48d1000cf542c50ffa0 title: 'Problem 289: Eulerian Cycles' challengeType: 5 forumTopicId: 301940 dashedName: problem-289-eulerian-cycles --- # --description-- Let C(x,y) be a circle passing through the points (x, y), (x, y+1), (x+1, y) and (x+1, y+1). For positive integers m and n, let E(m,n) be a configuration which consists of the m·n circles: { C(x,y): 0 ≤ x < m, 0 ≤ y < n, x and y are integers } An Eulerian cycle on E(m,n) is a closed path that passes through each arc exactly once. Many such paths are possible on E(m,n), but we are only interested in those which are not self-crossing: A non-crossing path just touches itself at lattice points, but it never crosses itself. The image below shows E(3,3) and an example of an Eulerian non-crossing path. Let L(m,n) be the number of Eulerian non-crossing paths on E(m,n). For example, L(1,2) = 2, L(2,2) = 37 and L(3,3) = 104290. Find L(6,10) mod 1010. # --hints-- `euler289()` should return 6567944538. ```js assert.strictEqual(euler289(), 6567944538); ``` # --seed-- ## --seed-contents-- ```js function euler289() { return true; } euler289(); ``` # --solutions-- ```js // solution required ```