| Clue | Source | Date |
|---|---|---|
| Progression of numbers with a constant ratio between successive terms ... or what 17, 27 and 44 Across feature? | The Chronicle of Higher Education | 21 Jul 2017 |
| Progression of numbers with a constant ratio between successive terms ... or what 17, 27 and 44 Across feature? | ||
| 9 + 3 + 1 + 1/3 + 1/9 + ..., e.g. |