The powers of 11 pattern prints one number per line, starting at 1 and multiplying by 11 each row.
Rule: res starts at 1; each next row is res * 11
1
11
121
1331
14641 ← n = 5Follows the concentric diamond in Program 47; next is the multiplication triangle in Program 49.
One loop, one running variable — print, then multiply by 11.
| Method | Idea | Best for |
|---|---|---|
| Print then multiply | print(res); res *= 11 | Cleanest loop body |
| If on first row | if i == 1: res = 1; else: res *= 11 | Matching older textbook code |
res = 1
for i from 1 to n:
print res
res = res * 11| Goal | Pattern |
|---|---|
| Start value | res = 1 |
| Loop rows | for i in range(1, n + 1): |
| Print line | print(res) |
| Next term | res *= 11 |
| API | Effect | Use for |
|---|---|---|
print(res) | Prints the value and ends the line | Preferred — one call per row |
print(res, end="") + print() | Same result in two calls | Rare here — not needed for this pattern |
Same idea as C# WriteLine(res): one value per line. Bare print(res) is enough — no end="" needed.
Change the row count and the powers-of-11 sequence updates instantly.
n = 5Trace res before and after each multiply.
| Row | Then res *= 11 | |
|---|---|---|
1 | 1 | 11 |
2 | 11 | 121 |
3 | 121 | 1331 |
4 | 1331 | 14641 |
5 | 14641 | 161051 (not printed) |
One print and one multiply per row — total work is linear in n.
Three complete programs: fixed 5 rows with an if-check, input() rows, and a clean print-then-multiply loop. Use View Output for sample results.
n = 5Textbook-style if on the first row, then multiply for later rows.
res = 0
for i in range(1, 6):
if i == 1:
res = 1
else:
res = res * 11
print(res)1. First row. When i == 1, set res = 1 and print it.
2. Later rows. Multiply the previous res by 11, then print.
3. Newline. Bare print(res) ends each row automatically.
Read the row count with input() and build the same sequence.
try:
n = int(input("Enter number of rows: "))
except ValueError:
print("Please enter a positive whole number.")
raise SystemExit(1)
if n < 1:
print("Please enter a positive whole number.")
raise SystemExit(1)
res = 0
for i in range(1, n + 1):
if i == 1:
res = 1
else:
res = res * 11
print(res)1. Validate n. Catch ValueError; require n >= 1.
2. Same sequence. Only the loop bound changes from the literal 5 to the user value.
3. Safer input tip. Cap demos for readable output:
if n < 1 or n > 8:
print("Enter a whole number from 1 to 8.")
raise SystemExit(1)Cleaner loop — no if. Print the current value, then advance.
res = 1
for i in range(5):
print(res)
res *= 111. Print current. Start with res = 1; each iteration prints the current value.
2. Advance. res *= 11 prepares the next row — no if needed.
Check these before calling the solution done.
If you do res *= 11 before printing when res starts at 1, the first line becomes 11. Print first.
11**n balloons quickly. Start with small n (like 5) while learning — Python still handles big ints fine.
You get 1, 10, 100, 1000… Keep the factor 11.
Output is just 1 — valid and useful for testing.
After 14641, carries appear (161051). Digits no longer match binomial coefficients.
ValueErrorBare int(input()) crashes on non-numeric text — wrap it in try/except ValueError.
| Program | Time | Extra space |
|---|---|---|
| Fixed / clean (Examples 1, 3) | O(n) | O(1) |
| User input (Example 2) | O(n) | O(1) |
One multiply and one print per row — linear in the number of rows (unlike nested-loop patterns).
print(res); res *= 11 — no if needed.print already adds the newline.O(n) time; O(1) extra space.One line: print the current power-of-11 term, then multiply by 11 for the next row.
Start with res = 1, print it, then update with res *= 11 each row. The first five lines are 1, 11, 121, 1331, 14641 — one value per line, O(n) time. Python handles big integers automatically.
Print a triangle where each cell is the product of its row and column indices.
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