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A349991 For any n >= 0, consider a sandpile model on the infinite hexagonal lattice starting with n grains at the origin, the other sites being empty; a(n) gives the number of nonempty sites after stabilization of this sandpile model.

Table of values

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

List of values

[0, 1, 1, 1, 1, 1, 6, 7, 7, 7, 7, 7, 6, 7, 7, 7, 7, 7, 6, 7, 7, 7, 7, 7, 6, 7, 7, 7, 7, 7, 6, 7, 7, 7, 7, 7, 18, 19, 19, 19, 19, 19, 18, 19, 19, 19, 19, 19, 18, 19, 19, 19, 19, 19, 18, 19, 19, 19, 19, 19, 18, 19, 19, 19, 19, 19, 18, 19, 19, 19, 19, 19, 24, 25]

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