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This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A308803 a(n) is the largest n-digit palindrome that is the product of two numbers having an equal number of digits, or 0 if no such palindrome exists.

Table of values

n a(n)
1 9
2 0
3 999
4 9009
5 99999
6 906609
7 9999999
8 99000099
9 999969999
10 9966006699
11 99999999999
12 999000000999
13 9999998999999
14 99956644665999
15 999999999999999
16 9999000000009999
17 99999999799999999
18 999900665566009999
19 9999999997999999999
20 99999834000043899999
21 999999999999999999999
22 9999994020000204999999
23 99999999999899999999999

List of values

[9, 0, 999, 9009, 99999, 906609, 9999999, 99000099, 999969999, 9966006699, 99999999999, 999000000999, 9999998999999, 99956644665999, 999999999999999, 9999000000009999, 99999999799999999, 999900665566009999, 9999999997999999999, 99999834000043899999, 999999999999999999999, 9999994020000204999999, 99999999999899999999999]

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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