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From: Ben Bacarisse <ben.usenet@bsb.me.uk>
Newsgroups: comp.lang.javascript
Subject: Re: Primality sieve challenge
Date: Mon, 25 Jan 2016 00:21:59 +0000
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"Chris M. Thomasson" <nospam@no-spam.ws> writes:

> On 1/23/2016 5:54 PM, Michael Haufe (TNO) wrote:
>>> On Friday, January 22, 2016 at 12:44:49 PM UTC-6, Stefan Weiss wrote:
>>> Pixel plots are often used to visually examine the randomness of series
>>> of numbers. For example, here's the output of V8's Math.random()
>>> function before and after the PRNG fix in December:
>>>
>>>    http://goo.gl/8M4kuk
>
>> Ulam Spirals:
>> <https://en.wikipedia.org/wiki/Ulam_spiral>
>
> FWIW, here is a little graph I did a while back:
>
> https://plus.google.com/101799841244447089430/posts/YeVfh7q5rD5

Very nice.

> Here is a excerpt:
> _______________________________________________
>  this graph is based on the x and y axis representing their respective
> primes. So the point (0,4) would the the 1st and 5th prime
> numbers. The point (1, 3) would the be the 2nd and 4th prime
> numbers. The color is based on how far apart they are from each
> other. So, the distance of point (0, 1) would be abs(2 - 3).

But this could be a bit clearer.  I want to know where the origin is
(top left?), and I'd word it like this: "In this graph the colour of
point (n, m) is determined by abs(p_n - p_m) i.e. by the difference
between the nth and mth prime, numbered from 0 (p_0 = 2, p_1 = 3, etc)."

I'd like to know what the integer to colour mapping is, too.

<snip>
-- 
Ben.