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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.

A211980 Triangle read by rows: T(n,k) = total number of regions in the last n-k+1 shells of n.

Table of values

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

List of values

[1, 2, 1, 3, 2, 1, 5, 4, 3, 2, 7, 6, 5, 4, 2, 11, 10, 9, 8, 6, 4, 15, 14, 13, 12, 10, 8, 4, 22, 21, 20, 19, 17, 15, 11, 7, 30, 29, 28, 27, 25, 23, 19, 15, 8, 42, 41, 40, 39, 37, 35, 31, 27, 20, 12, 56, 55, 54, 53, 51, 49, 45, 41, 34, 26, 14, 77, 76, 75]

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

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