Timothy J. Rolfe
Abstract
This article explores various optimizations that can be used to speed the discovery of Armstrong numbers (also known as Narcissistic numbers), which are n-digit numbers that are the sum of the nth powers of their digits. Optimizations include comparing the parity of the least-significant digit of the number and that of the sum of its digits, using a dynamic programming approach for the powers of digits, examining the parity of the sum of digits excluding the least-significant digit, and computing forward bounds on the possible numbers and on the possible sums of dn. The final optimization completes in about 2% of the time of the initial implementation.
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Index Terms
- Optimizations generating Armstrong numbers
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