Generate Rows creates a sequence from an initial expression, a condition and a loop expression. The initial expression produces the first candidate. The condition decides whether that candidate is emitted. The loop expression advances it before the condition is checked again. An inclusive <= condition includes the endpoint when the sequence reaches it.
When the tool has an input stream, it can generate a sequence for each incoming record. Use a source field for a per-record endpoint rather than typing the first visible value into the condition. A loop that never changes its field cannot finish. A loop that advances in the wrong direction can also run beyond the intended bounds. Check the first and last output records and the count for each source record before using the generated rows downstream.