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.

A307105 Number of rational numbers which can be constructed from the set of integers between 1 and n, through a combination of multiplication and division.

Table of values

n a(n)
0 1
1 1
2 3
3 9
4 21
5 63
6 117
7 351
8 621
9 1161
10 2043
11 6129
12 8631
13 25893
14 45135
15 71685
16 102285
17 306855
18 420309
19 1260927
20 1755513
21 2671299
22 4571073
23 13713219
24 17156853
25 25778169
26 43930755
27 59315085
28 80765235
29 242295705
30 295267275
31 885801825

List of values

[1, 1, 3, 9, 21, 63, 117, 351, 621, 1161, 2043, 6129, 8631, 25893, 45135, 71685, 102285, 306855, 420309, 1260927, 1755513, 2671299, 4571073, 13713219, 17156853, 25778169, 43930755, 59315085, 80765235, 242295705, 295267275, 885801825]

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

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