Python Repeating Number Triangle Pattern (Descending)
Beginner
5 min read
Updated: Sep 2026
3 programs
Live preview
Definition
What Is This Pattern?
A descending repeating number triangle prints digit i repeated rows - i + 1 times, counting i down from rows.
Remember
Rule: for i = n..1, print i exactly (n - i + 1) times
5
44
333
2222
11111 ← 5 rows
In Python you solve it with two nested for loops: the outer loop picks the digit, the inner loop repeats it with print(i, end=""), then bare print() ends the row. Program 9 is the ascending twin (1, 22, 333…).
Approach
How to Solve It
Outer loop counts down from rows to 1. Inner loop repeats digit i exactly rows - i + 1 times. End each row with print().
Method
Idea
Best for
Nested loops
Outer picks digit n..1; inner repeats it n-i+1 times
Learning, interviews, exams
str(i) * count
Build each full row in one call
Leaner demos once loops click
Pseudocode
Pseudocode
for i from rows down to 1:
for j from rows down to i:
print i (no newline)
print newline
Cheat sheet
Goal
Pattern
Pick digit (count down)
for i in range(rows, 0, -1):
Repeat digit i
for j in range(rows, i - 1, -1): print(i, end="")
End the row
print()
String multiply form
print(str(i) * (rows - i + 1))
Ascending twin (Program 9)
for i in range(1, rows + 1): with print(i, end="") repeated i times
Printing Numbers vs Starting a New Line
API
Effect
Use for
print(i, end="")
Stays on the same line
Each repeat of digit i
print()
Ends the current line
After the inner loop
Print all repeats without a newline, then end the row once.
Try it
Live Preview
Change the row count and the repeating triangle updates instantly — capped at 9 so every digit stays a single character.
Whole numbers from 1 to 9 (single digits). Tap a chip or type a value — the preview redraws as you go.
Live result5 rows · 15 digits
5
44
333
2222
11111
Trace
Worked Walkthrough
Trace rows = 4 — each outer-loop value of i, how many times the inner loop runs, and the printed row.
i
Inner j
Repeats
Printed row
4
4..4
1
4
3
4..3
2
33
2
4..2
3
222
1
4..1
4
1111
Total digits are 1+2+3+4 = 10 — the triangular number n(n+1)/2.
Code
Python Programs
Three complete programs: fixed height, input(), and a string-multiply shortcut. Use View Output for sample results.
Example 1 — Fixed rows = 5
Outer loop picks the digit; inner loop repeats it rows - i + 1 times.
Python
rows = 5
for i in range(rows, 0, -1):
for j in range(rows, i - 1, -1):
print(i, end="")
print()
Output
5
44
333
2222
11111
How It Works
1. Count down.for i in range(rows, 0, -1) yields 5, 4, 3, 2, 1 — the digit for each row.
2. Grow repeats. When i = 5, the inner loop runs once (5); when i = 1, it runs five times (11111).
3. Newline. Bare print() after the inner loop starts the next longer row of a smaller digit.
Example 2 — User Input
Read the row count from the keyboard. Prefer a try / except in real apps (shown in the tip below).
Python
rows = int(input("Enter the number of rows: "))
for i in range(rows, 0, -1):
for j in range(rows, i - 1, -1):
print(i, end="")
print()
Output (when user enters 4)
Enter the number of rows: 4
4
33
222
1111
How It Works
1. Read rows.input() returns a string; int(...) converts it to a whole number.
2. Same nested loops. Four rows start at 4 and end at 1111.
3. Safer input tip. Bare int(input()) raises ValueError on letters. Prefer:
Safer input
raw = input("Enter the number of rows: ").strip()
try:
rows = int(raw)
except ValueError:
print("Enter a positive whole number.")
raise SystemExit(1)
if rows < 1:
print("Enter a positive whole number.")
raise SystemExit(1)
Example 3 — String Multiply Shortcut
Same shape with one call per row — best once the rows - i + 1 count is clear.
Python
rows = 5
for i in range(rows, 0, -1):
print(str(i) * (rows - i + 1))
Output
5
44
333
2222
11111
How It Works
1. Count still matters.rows - i + 1 is the same repeat length the inner loop used.
2. Same shape. Identical output to Example 1 — keep the nested-loop version for exams that expect two loops.
3. Convert first.str(i) * count needs a string — multiplying an int would raise an error.
Edge Cases & Pitfalls
Check these before calling the solution done.
wrong twin
for i in range(1, rows + 1) with print(i) × i
That is Program 9 (1, 22, 333). Keep counting down and growing repeats for this pattern.
print() inside
Bare print(i) inside the inner loop
That puts each digit on its own line. Use print(i, end="") for repeats; call bare print() only after the row finishes.
wrong count
range(1, i + 1) instead of range(rows, i - 1, -1)
The inner bound must run rows - i + 1 times so repeats grow as the digit shrinks.
rows = 1
Single digit
Output is just 1 — a good sanity check.
rows ≤ 0
Empty output
The outer loop never runs. Validate and prompt again for clearer UX.
multi-digit
rows > 9
print(10, end="") prints two characters. Labs usually stick to 1–9 for a clean single-digit look.
Analysis
Time and Space Complexity
Program
Time
Extra space
Nested loops (Examples 1–2)
O(n²)
O(1)
String multiply (Example 3)
O(n²)
O(1) beyond the row string
There are n rows printing 1+2+…+n digits, so total work is n(n+1)/2.
Remember
Key Takeaways
Rule: for i = n..1, print digit i exactly n - i + 1 times.
Inner bound:range(rows, i - 1, -1) grows the repeat count as the digit shrinks.
end= vs print(): repeats stay on the line; bare print() advances after each row.
Next step: Program 11 inverts the triangle (longest row of the top digit first).
One line: for each digit from n down to 1, print it n-i+1 times with end="", then call print().
Frequently Asked Questions
The outer loop decreases i from rows down to 1. The inner loop runs j from rows down to i, so it executes once when i equals rows, twice when i is rows-1, and so on until rows times for i = 1.
for j in range(rows, i - 1, -1) runs (rows - i + 1) times. That count grows as i shrinks, which is why 4 prints twice, 3 prints three times, and 1 prints rows times.
print(i, end="") stays on the same line. print() ends the current line. Repeated digits use end=""; the row break uses print() after the inner loop.
Program 9 grows upward: row i repeats digit i exactly i times (1, 22, 333). Program 10 starts with one copy of the top digit and increases repeats as the digit decreases (5, 44, 333, 2222, 11111).
O(n²) where n is the number of rows. Total print calls equal 1+2+…+n = n(n+1)/2.
Yes. print(str(i) * (rows - i + 1)) prints a full row in one call. Nested loops are better for learning; str(i) * count is a handy shortcut once the bounds make sense.
Wrap int(input()) in try/except ValueError, or check that the raw string is digits, and require rows >= 1.
The outer loop never runs, so nothing is printed. Validate and prompt again if you want a clear user message.
🤔
Did you know?
Row digit i repeats rows - i + 1 times. The outer loop counts down from rows, so the first row shows one copy of the top digit and the last row repeats 1 for rows times — still O(n²) total prints.
