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.

A143823 Number of subsets {x(1),x(2),...,x(k)} of {1,2,...,n} such that all differences |x(i)-x(j)| are distinct.

Table of values

n a(n)
0 1
1 2
2 4
3 7
4 13
5 22
6 36
7 57
8 91
9 140
10 216
11 317
12 463
13 668
14 962
15 1359
16 1919
17 2666
18 3694
19 5035
20 6845
21 9188
22 12366
23 16417
24 21787
25 28708
26 37722
27 49083
28 63921
29 82640
30 106722
31 136675
32 174895
33 222558
34 283108
35 357727
36 451575
37 567536
38 712856
39 890405
40 1112081
41 1382416
42 1717540

List of values

[1, 2, 4, 7, 13, 22, 36, 57, 91, 140, 216, 317, 463, 668, 962, 1359, 1919, 2666, 3694, 5035, 6845, 9188, 12366, 16417, 21787, 28708, 37722, 49083, 63921, 82640, 106722, 136675, 174895, 222558, 283108, 357727, 451575, 567536, 712856, 890405, 1112081, 1382416, 1717540]