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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.

A317593 Take a number z of x digits and consider any concatenation z = concat(y_1, y_2, ..., y_i) where y_1, y_2, ..., y_i have the same number of digits. Then let f(z) be the sum of the products y_1*y_2*...*y_i for all those concatenations. Sequence lists numbers z such that f(f(z)) = z. (see example.)

Table of values

n a(n)
1 1488
2 2992
3 5692
4 101875
5 165864
6 207712
7 425830
8 569953
9 872539
10 20988160
11 25768720
12 26645280
13 48218580
14 48418542
15 50519902
16 1055195775
17 1175196540
18 1661395240
19 1971592669
20 2056199802
21 2601999369
22 3016199710
23 3068196150
24 3545196660
25 3835794250
26 3896098816
27 5520199708

List of values

[1488, 2992, 5692, 101875, 165864, 207712, 425830, 569953, 872539, 20988160, 25768720, 26645280, 48218580, 48418542, 50519902, 1055195775, 1175196540, 1661395240, 1971592669, 2056199802, 2601999369, 3016199710, 3068196150, 3545196660, 3835794250, 3896098816, 5520199708]

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

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