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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.

A293772 Let P be the sequence of distinct lattice points defined by the following rules: P(1) = (0,0), P(2) = (1,0), and for any i < j < k, P(k) does not lie on the vector (P(i), P(j)), and for any n > 2, P(n) is the closest lattice point to P(n-1) such that the angle of the vectors (P(n-2), P(n-1)) and (P(n-1), P(n)), say t, satisfies 0 < t <= Pi/2, and in case of a tie, minimize the angle t; a(n) = X-coordinate of P(n).

Table of values

n a(n)
1 0
2 1
3 1
4 0
5 -1
6 -1
7 0
8 2
9 2
10 1
11 0
12 -1
13 -2
14 -2
15 -1
16 1
17 3
18 3
19 2
20 1
21 -1
22 -2
23 -3
24 -3
25 -2
26 -1
27 1
28 2
29 4
30 4
31 3
32 2
33 0
34 -3
35 -4
36 -4
37 -3
38 -2
39 -1
40 1
41 2
42 3
43 4
44 4
45 3
46 1
47 -2
48 -5
49 -5
50 -4
51 -1
52 0
53 1
54 3
55 4
56 5
57 5
58 4
59 3
60 1
61 -2
62 -3
63 -6
64 -6
65 -5
66 -3
67 0
68 1
69 2
70 3
71 4
72 5
73 5
74 4
75 2
76 -1
77 -4

List of values

[0, 1, 1, 0, -1, -1, 0, 2, 2, 1, 0, -1, -2, -2, -1, 1, 3, 3, 2, 1, -1, -2, -3, -3, -2, -1, 1, 2, 4, 4, 3, 2, 0, -3, -4, -4, -3, -2, -1, 1, 2, 3, 4, 4, 3, 1, -2, -5, -5, -4, -1, 0, 1, 3, 4, 5, 5, 4, 3, 1, -2, -3, -6, -6, -5, -3, 0, 1, 2, 3, 4, 5, 5, 4, 2, -1, -4]

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