A166497 A Per Bak sand pile collapse sequence using A147665 in the A153112 form.

1, 1, 1, 1, 2, 3, 2, 2, 3, 2, 2, 3, 2, 2, 3, 2, 2, 4, 3, 2, 4, 3, 2, 4, 3, 2, 5, 1, 2, 2, 2, 2, 3, 2, 2, 4, 3, 2, 4, 3, 2, 4, 3, 2, 5, 4, 3, 5, 4, 2, 5, 5, 5, 5, 4, 3, 6, 3, 2, 4, 4, 4, 4, 3, 2, 5, 4, 3, 5, 5, 5, 6, 3, 2, 7, 3, 2, 4, 5, 6, 5, 4, 3, 4, 3, 2, 4, 3, 2, 4, 1, 2, 2, 2, 2, 3, 2, 2, 4, 3, 2, 4, 3, 2, 4

Offset: 0

Author

Roger L. Bagula, Oct 15 2009

Keywords

• nonn
• uned

References

• Per Bak, "How nature works, the science of self-organized criticality", Springer-Verlag, New York, 1996, pages 49-64

Crossrefs

Cf. A153112, A147665.

Programs

Mathematica

f[0] = 1; f[1] = 1; f[2] = 1;
f[n_] := f[n] = If[Mod[Floor[Sum[f[i], {i, 0, n - 1}]/2], 2^(4 + Mod[n, 3])] == 1, 1 + Mod[n, 3], f[f[n - 1]] + If[Mod[n, 3] == 0, f[f[n/3]], If[Mod[n, 3] == 1, f[f[(n - 1)/3]], f[n - f[(n - 2)/3]]]]];
Table[f[n], {n, 0, 200}]