Von Neumann's 1949 middle-square PRNG --- famously degenerates to short cycles. Square the state, extract middle digits. Exhibits visible lattice structure.
Standard analysis sees: anti-persistent; homoskedastic; high-dimensional / space-filling; stationary. The atlas finds no named structure, but the source is distinctively extreme on Zipf–Mandelbrot (8-bit):entropy_nonstationarity (+4.5z) — beyond what the standard bank predicts for it. It sits beside Windows PE x86-64 in the atlas (standard-bank rank 131) — a neighbor conventional features miss.
Zipf–Mandelbrot (8-bit):entropy_nonstationarity | +4.5z | bank-miss 2.6σ |
Zipf–Mandelbrot (16-bit):zipf_r_squared | -2.5z | bank-miss 1.6σ |
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_(centered)/signed_log_z/Middle-Square_(von_Neumann).png)
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/phi_spectrum/Middle-Square_(von_Neumann).png)
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/default/Middle-Square_(von_Neumann).png)
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| Nearest neighbor | Distance | |
|---|---|---|
| Windows PE x86-64 | 4.40 | |
| Linux ELF x86-64 | 4.42 | |
| macOS Mach-O (dyld) | 4.46 |
Zipf–Mandelbrot (16-bit) › Zipf–Mandelbrot (16-bit):hapax_ratio | rank 4/307 | 0.9020 |
Zipf–Mandelbrot (8-bit) › Zipf–Mandelbrot (8-bit):entropy_nonstationarity | rank 3/307 | 0.5607 |