Armstrong number: n = Σdᵢᵏ where k = number of digits. k=3: 153=1³+5³+3³, 370, 371, 407. k=4: 1634, 8208, 9474. k=5: 54748, 92727, 93084. Find all Armstrong numbers for any digit count.
How to Use
Select digit count k:
- k: Number of digits
- List: All Armstrong numbers
- Test: Check any number
By Digit Count
- k=1: 1,2,...,9 (trivially)
- k=3: 153,370,371,407
- k=4: 1634,8208,9474
- k=5: 54748,92727,93084
- k=6: 548834
- k=7: 1741725,4210818,9800817,9926315
Algorithm
For k-digit Armstrong numbers: iterate all k-digit numbers (10ᵏ⁻¹ to 10ᵏ−1), compute Σdᵢᵏ, check if equals n. Optimization: use combinations of digits with repetition to reduce search space.
Step-by-Step Instructions
- 1Select k.
- 2Generate list.
- 3View breakdowns.
- 4Test a number.
- 5Compare digit counts.