The SEQUENCE function

Returns a list of numbers in sequence, such as 1, 2, 3, that spills into rows and columns. You choose the size, the start and the step.

Syntax

SEQUENCE(rows, [columns], [start], [step])
rows
How many rows to fill.
columns (optional)
How many columns to fill. Left out, 1.
start (optional)
The first number. Left out, 1.
step (optional)
How much each number goes up by. Left out, 1. A negative step counts down.

Examples

B1=SEQUENCE(5)
AB
11
22
33
44
55
B1=SEQUENCE(2,3,10,10)
ABCD
1102030
2405060

In plain words: Fill 2 rows and 3 columns, starting at 10 and counting up by 10.

B1=SUM(SEQUENCE(100))
AB
15050

Questions

How do I number a list that keeps growing?

Count the filled cells and let SEQUENCE spill that many numbers, as in =SEQUENCE(COUNTA(B2:B100)). Add a name to the list and the numbering grows with it.

Why does SEQUENCE return

The cells it needs are not empty. SEQUENCE(5) needs five free cells down from the formula; clear them and the numbers appear.

Related functions