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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.

A247013 Consider the prime factors, with multiplicity, in ascending order, of a composite number not ending in 0. Take their sum and repeat the process deleting the minimum number and adding the previous sum. The sequence lists the numbers that after some iterations reach a sum equal to the reverse of themselves.

Table of values

n a(n)
1 4
2 9
3 14
4 94
5 194
6 371
7 1887
8 1994
9 11282
10 25656
11 61081
12 66691
13 112082
14 394407
15 582225
16 4284191
17 5681778
18 9317913
19 9361072
20 9493615
21 19120874
22 75519134
23 92688481

List of values

[4, 9, 14, 94, 194, 371, 1887, 1994, 11282, 25656, 61081, 66691, 112082, 394407, 582225, 4284191, 5681778, 9317913, 9361072, 9493615, 19120874, 75519134, 92688481]

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

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