cp's OEIS Frontend

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.

A240466 Palindromes for which both the numerator (A017665) and the denominator (A017666) of sigma(n)/n are palindromes, where sigma is the sum of divisors (A000203).

Table of values

n a(n)
1 1
2 2
3 3
4 4
5 5
6 6
7 7
8 333
9 17571
10 40004
11 93939
12 569965
13 1787871
14 2316132
15 541626145
16 17575757571
17 5806270726085
18 7359770779537
19 520524424425025
20 17275787578757271
21 17878787578787871

List of values

[1, 2, 3, 4, 5, 6, 7, 333, 17571, 40004, 93939, 569965, 1787871, 2316132, 541626145, 17575757571, 5806270726085, 7359770779537, 520524424425025, 17275787578757271, 17878787578787871]

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

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