Exact target length
Generate from 1 to 10,000 items.
Input list0 B
Result0 B
Add at least one list item.
0items0non-empty0unique0duplicates0characters
List basics
Understanding lists
A deterministic sequence follows a rule, so the same settings produce the same output. Number sequences use a start and step; letter sequences use spreadsheet-style labels such as a, z, aa, and ab.
Custom sequences cycle through source items until the requested length is reached. Symmetry mirrors the generated half without duplicating the center unnecessarily.
What it does
What this tool does
Generate predictable sequences with exact length, direction, repetition, and separator control.
Number progressions
Use positive, negative, fractional, or zero steps.
Letters beyond z
Continue with aa, ab, and spreadsheet-style labels.
Custom cycles and symmetry
Repeat source items or mirror the sequence.
How to use
How to use it
Choose a sequence
Select numbers, letters, or custom items.
Set the rule
Enter start, step, source items, and target length.
Add symmetry if needed
Mirror the sequence while keeping the exact output count.
Export
Choose a separator, then copy or download the result.
Limits
Common errors and limits
Large output
Generation stops at 10,000 items to keep the page responsive.
Letter start values
Letter sequences use a 1-based index: 1 is a and 27 is aa.
FAQ
Frequently asked questions
Can it create descending numbers?
Yes. Use a negative step.
Can it continue after z?
Yes. It uses spreadsheet-style labels: aa, ab, and so on.
Can it repeat my own items?
Yes. Select Custom items and enable cycling.
Is this random?
No. This tool creates deterministic sequences; random picking and shuffling are available in Random List.