Course of Raku / Advanced / More about built-in types / Sequences / Sequence patterns
Quiz — The ... operator
What does the following program print?
say 1, 3, 9 ... 81;| 1 | (1 3 9 27 81) |
| 0 | (1 3 9 81) |
| 0 | (1 3 5 7 ... 81) |
| 0 | (3 9 27) |
With three seed values, ... looks at the ratio
between them: 1, 3, 9 each triple, so it continues
geometrically as 27, 81. (Two seeds would instead set an
arithmetic step.)