Primecoinchains: display any chain Primecoin has found instantly

Hey guys,

So in my spare time, I am working on a new project of mine

It lets you input a block height or block hash and displays you the prime chain within the given block.
I’m also working on a chain toplist feature and I hope to release it within this week.

Here’s how you could help me out:

I think there is an issue with how I calculate the bitwin chains. With the last numbers of the chain, (command: is prime xxxxxxxx) tends to tell me that this is not a prime number. That issue does not exist with Cunningham Chains.

Sunny King, or anyone keen on the subject: Could you help me and take a look at the calculated TWN chains?

Also, here is the thread over at reddit


Student piggy bank

Hi lacksfish,

Check Petr1fied code here:

The bi-twin chain is derived from origin by subtracting and adding 1, then doubling the origin and do the same again.

Good work!

Hey, thanks for your input, that’s exactly what I’m doing so far.
Still, some of the later TWN chain pieces rarely are prime.

Check your genesis block (block 0) for example on my page.

the last number,
doesn’t seem to be prime based on wolfram alphas output

Any help/idea is greatly appreciated!

Sunny King can likely answer better then I can, but I’m pretty sure that the primecoin protocol doesn’t guarantee or require the numbers to be exactly prime, just probabilistically prime. Thus, as you have found, some of the primechains found in the block chain aren’t true prime chains.

Genesis block is TWN06 type, so there are only 6 primes in the prime chain, not 12 as shown in your page.

You can compare notes with this crawler:

Regarding refer_2_me’s comment, even though the protocol allows certain pseudoprimes to pass block checks, due to the rarity of pseudoprimes I don’t think there is any pseudoprime in the entire block chain. But do let me know if a pseudoprime is found.

Thanks for the info. I assumed from your paper that they would be more common. I’ll have to go re-read it.

Thanks for explaining the bitwin chains! I got it to work as it should.

Is there anything you would like to see implemented in the site? Your opinion (and everyone else’s) is highly appreciated.