n=15: 825 reachable points with |B|<=40, 181 direction classes
distinct patterns: class | (preclosed length / shortest , reduced factor) ... | unreduced factor tuples -> number of direction classes
  class -    | 1.00000:x1  1.95630:x1  2.82709:x1  3.57433:x1  4.16535:x1  4.57433:x1  4.78339:x1 | {(1, 1, 1, 1, 1, 1, 1): 5} | n among reduced factors: False
  class -    | 1.00000:x3  1.95630:x3  2.82709:x1  3.57433:x3  4.16535:x3  4.57433:x1  4.78339:x3 | {(3, 3, 1, 3, 3, 1, 3): 22} | n among reduced factors: False
  class -    | 1.00000:x5  1.95630:x5  2.82709:x5  3.57433:x5  4.16535:x1  4.57433:x5  4.78339:x5 | {(5, 5, 5, 5, 1, 5, 5): 38} | n among reduced factors: False
  class -    | 1.00000:x15  1.95630:x15  2.82709:x5  3.57433:x15  4.16535:x3  4.57433:x5  4.78339:x15 | {(15, 15, 5, 15, 3, 5, 15): 116} | n among reduced factors: True
longest closed trajectory met: 1530 bounces
direction classes with a reduced factor equal to n: 116 of 181
Theorem 7(b) on these direction classes: classes 181 ; with exactly m=7 bands of distinct preclosed length: 181 ; preclosed lengths proportional to sin(2j pi/n): 181 ; factors = n/gcd(n, alpha*j) for some alpha: 181 ; gcd(alpha, n) -> number of classes: {1: 116, 3: 38, 5: 22, 15: 5}
exact decisions: 219310, time 14.5s
