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A166493 A Per Bak sand pile collapse sequence using Hofstadter Q:A005185, of the A153112 form. +0
1
1, 1, 1, 2, 3, 3, 4, 5, 5, 6, 6, 6, 8, 8, 8, 10, 9, 10, 1, 7, 15, 12, 11, 14, 14, 12, 16, 16, 16, 16, 16, 20, 17, 17, 20, 11, 21, 25, 18, 20, 26, 22, 24, 19, 27, 17, 23, 30, 13, 28, 36, 24, 25, 32, 27, 30, 32, 28, 32, 36, 30, 32, 3, 50, 40, 22, 43, 31, 37, 35, 28, 40, 44, 33, 38, 49 (list; graph; listen)
OFFSET

0,4

COMMENT

This sequence shows two unique effects:

1) a break down to cyclic behavior three collapses in at about n=600

2) entropy plateau that correspond to the collapses:

e = Table[N[ -Log[f[n]/fm]*(f[n]/fm)], {n, 0, 1000}];

ListPlot[e, PlotJoined -> True, PlotRange -> All]

A153112 , the sand pile sequence based on A004001,

This plateau entropy effect is important because

it drives the self-organization in evolutionary processes

in biology. show the second effect, but no breakdown.

MATHEMATICA

Clear[f, n]; 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])] == 0,

1 + Mod[n, 3],

f[n - f[n - 1]] + f[n - f[n - 2]]];

a = Table[f[n], {n, 0, 200}]

CROSSREFS

Cf. A153112, A004001, A005185

Sequence in context: A094606 A080595 A123579 this_sequence A005185 A119466 A100922

Adjacent sequences: A166490 A166491 A166492 this_sequence A166494 A166495 A166496

KEYWORD

nonn,uned

AUTHOR

Roger L. Bagula (rlbagulatftn(AT)yahoo.com), Oct 15 2009

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Last modified November 29 12:46 EST 2009. Contains 167659 sequences.


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