Numbers whose Digits are Unchanged when Subtracting Reversal
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Theorem
The following sequence consists of the integers which have the property that subtraction of their reversals results in anagrams of them:
- $954, 1980, 2961, 3870, 5823, 7641, 9108, 19980, 29880, 29961, 32760, \ldots$
This sequence is A121969 in the On-Line Encyclopedia of Integer Sequences (N. J. A. Sloane (Ed.), 2008).
Proof
\(\ds 954 - 459\) | \(=\) | \(\ds 495\) | ||||||||||||
\(\ds 1980 - 0891\) | \(=\) | \(\ds 1089\) | ||||||||||||
\(\ds 2961 - 1692\) | \(=\) | \(\ds 1269\) | ||||||||||||
\(\ds 3870 - 0783\) | \(=\) | \(\ds 3087\) | ||||||||||||
\(\ds 5823 - 3285\) | \(=\) | \(\ds 2538\) | ||||||||||||
\(\ds 7641 - 1467\) | \(=\) | \(\ds 6174\) | ||||||||||||
\(\ds 9108 - 8019\) | \(=\) | \(\ds 1089\) | ||||||||||||
\(\ds 19 \, 980 - 08 \, 991\) | \(=\) | \(\ds 10 \, 989\) | ||||||||||||
\(\ds 29 \, 880 - 08 \, 892\) | \(=\) | \(\ds 20 \, 988\) | ||||||||||||
\(\ds 29 \, 961 - 16 \, 992\) | \(=\) | \(\ds 12 \, 969\) | ||||||||||||
\(\ds 32 \, 760 - 06 \, 732\) | \(=\) | \(\ds 26 \, 037\) |
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Sources
- 1986: David Wells: Curious and Interesting Numbers ... (previous) ... (next): $1980$
- 1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $1980$