File:Ulam spiral centred on 41.png
Summary
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English: This is a variation on the Ulam Spiral, centred on the number 41 rather than the usual value of 1. Black squares represent prime numbers when the integers are written in order spiralling out from 41 at the centre. The distinctive black diagonal from bottom left to top right through the middle represents primes of the form n² + n + 41. The central part of this line shows an unbroken run of 40 of such primes. Other fragments of diagonal lines correspond to other prime-generating quadratic expressions. |
| Date | |
| Source | Used macros in Excel to generate the spiral and conditional formatting to highlight the primes. |
| Author | TrulyBlue |
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