Hofstadter Q

number-theory · 37 views
number-theoryarithmetic

What It Is

Hofstadter Q-sequence (A005185): Q(1)=Q(2)=1, Q(n)=Q(n-Q(n-1))+Q(n-Q(n-2)). Quasi-chaotic nested recurrence with no closed form; not proven well-defined for all n, though empirically holds far past the ranges sampled here. Q(n) ~ n/2 with Mallows-conjectured O(√n) fluctuations, so the emitted first differences Q[n]-Q[n-1] form an integer stream with AC1 ~ -0.5 (oscillatory: big drops followed by big rises) and a slowly-ramping variance over the window --- nonstationary by design, not a generator artifact. Trending metrics (variance_trend, vol_of_vol) respond to the ramp; that is faithful detection of Q's mathematical structure, not noise.

Interpretation

Standard analysis sees: anti-correlated (alternating); anti-persistent; blue spectrum (high-frequency power). The atlas finds no named structure, but the source is distinctively extreme on Spectral Analysis:spectral_slope (+2.4z) — beyond what the standard bank predicts for it.

What standard analysis sees
tail heaviness0.72
asymmetry0.59
occupancy0.50
short-range corr0.05
long-range memory0.05
spectral colour0.99
periodicity0.26
complexity0.76
time-irreversibility0.41
volatility clustering0.49
multifractality0.42
dimensionality0.49
nonstationarity0.79
What the atlas adds
Atlas-extreme metrics the standard bank can’t predict for this source
Spectral Analysis:spectral_slope+2.4zbank-miss 1.3σ

Composition

dtypeint64
range[-6758, 6476]
unique values5308 / 16384
mean ± std0.489 ± 1.33e+03

Render Gallery

Atlas Position

Nearest neighborDistance
Blue Noise3.68cross-origin
Coupled Map Lattice3.71cross-origin
IMS Bearing Degraded3.91cross-origin

Open in Atlas →

Which Geometries Light Up

AutoRegressiveAutoRegressive:ar_coef_1rank 305/307-1.5848
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