Palindromic Squares with Non-Palindromic Roots
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Theorem
The sequence of palindromic squares with non-palindromic square roots begins:
- $676, 69 \, 696, 94 \, 249, 698 \, 896, 5 \, 221 \, 225, 6 \, 948 \, 496, 522 \, 808 \, 225, \ldots$
This sequence is not explicitly given in On-Line Encyclopedia of Integer Sequences (N. J. A. Sloane (Ed.), 2008).
The sequence of those corresponding non-palindromic square roots begins:
- $26, 264, 307, 836, 2285, 2636, 22 \, 865, 24 \, 846, 30 \, 693, \ldots$
This sequence is A251673 in the On-Line Encyclopedia of Integer Sequences (N. J. A. Sloane (Ed.), 2008).
Proof
By investigating all square numbers which are palindromic.
\(\ds 676\) | \(=\) | \(\ds 26^2\) | ||||||||||||
\(\ds 69 \, 696\) | \(=\) | \(\ds 264^2\) | ||||||||||||
\(\ds 94 \, 249\) | \(=\) | \(\ds 307^2\) | ||||||||||||
\(\ds 698 \, 896\) | \(=\) | \(\ds 836^2\) | ||||||||||||
\(\ds 5 \, 221 \, 225\) | \(=\) | \(\ds 2285^2\) | ||||||||||||
\(\ds 6 \, 948 \, 496\) | \(=\) | \(\ds 2636^2\) | ||||||||||||
\(\ds 522 \, 808 \, 225\) | \(=\) | \(\ds 22 \, 865^2\) |
and so on.
$\blacksquare$
Sources
- 1986: David Wells: Curious and Interesting Numbers ... (previous) ... (next): $676$
- 1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $676$