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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.

A280026 Fill an infinite square array by following a spiral around the origin; in the n-th cell, enter the number of earlier cells that can be seen from that cell.

Table of values

n a(n)
0 0
1 1
2 2
3 3
4 3
5 4
6 4
7 5
8 6
9 5
10 6
11 7
12 6
13 7
14 8
15 9
16 7
17 8
18 9
19 10
20 8
21 9
22 10
23 11
24 12
25 9
26 10
27 11
28 12
29 13
30 10
31 11
32 12
33 13
34 14
35 15
36 11
37 12
38 13
39 14
40 15
41 16
42 12
43 13
44 14
45 15
46 16
47 17
48 18
49 13
50 14
51 15
52 16
53 17
54 18
55 19
56 14
57 15
58 16
59 17
60 18
61 19
62 20
63 21
64 15
65 16
66 17
67 18
68 19
69 20
70 21

List of values

[0, 1, 2, 3, 3, 4, 4, 5, 6, 5, 6, 7, 6, 7, 8, 9, 7, 8, 9, 10, 8, 9, 10, 11, 12, 9, 10, 11, 12, 13, 10, 11, 12, 13, 14, 15, 11, 12, 13, 14, 15, 16, 12, 13, 14, 15, 16, 17, 18, 13, 14, 15, 16, 17, 18, 19, 14, 15, 16, 17, 18, 19, 20, 21, 15, 16, 17, 18, 19, 20, 21]

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