5 ms·

P+41 spiral is absolutely fascinating. [1] I really want to know why they cluster there. http://www.numberspiral.com/art/14.gif http://www.numberspiral.com/art

by therein 10y ago

P+41 spiral is absolutely fascinating. [1] I really want to know why they cluster there. http://www.numberspiral.com/art/14.gif http://www.numberspiral.com/art/14.gif

stephengillie 10y ago
It's difficult to visually diff these on mobile, but P+41 appears to mirror S-9. http://www.numberspiral.com/art/8.gif http://www.numberspiral.com/art/8.gif
imglorp 10y ago
There is a prime generating formula n^2 + n + 41 for n=0 to 39. Maybe this is related? http://mathworld.wolfram.com/Prime-GeneratingPolynomial.html http://mathworld.wolfram.com/Prime-GeneratingPolynomial.html
- erk__ 10y ago
  Yes it is, it is a bit hidden on the left side on the page in a details box.
- akhalr 10y ago
  This also holds for n = -1. Not much real benefit; just extends the set of n to 41 consecutive integers.
cperciva 10y ago
The P+41 spiral contains an unusually large number of primes because 163 is a Heegner number (https://en.wikipedia.org/wiki/Heegner_number https://en.wikipedia.org/wiki/Heegner_number).