Block #323,034

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/21/2013, 9:46:30 AM · Difficulty 10.1979 · 6,484,819 confirmations

2CC
Cunningham Chain of the Second Kind

A sequence where each prime is double the previous prime minus one.

Block Header
Block Hash
f9f54ef49c9ab076c8dfa6c945ba863122db2de03ae8a5f5965319bc1a7ef8c3

Height

#323,034

Difficulty

10.197914

Transactions

1

Size

1.05 KB

Version

2

Bits

0a32aa79

Nonce

2,060

Timestamp

12/21/2013, 9:46:30 AM

Confirmations

6,484,819

Merkle Root

fc5765fa98dc5b54b50262aeb37ca4257df77f7473d1d0afc10405823a27600c
Prime Chain Origin

This is the prime chain origin stored in the block header. It is a composite number (not prime itself) — it equals the first prime in the chain multiplied by a primorial. The origin anchors the entire chain to this specific block.

1.306 × 10⁹⁹(100-digit number)
13062538975833955398…93420406219202074561
Discovered Prime Numbers
p_k = 2^k × origin + 1

These are the actual prime numbers discovered by this block, computed using the verified Primecoin formula. Each number has been independently confirmed to pass the Fermat primality test. Use the FactorDB links to verify any number independently.

1
origin + 1
1.306 × 10⁹⁹(100-digit number)
13062538975833955398…93420406219202074561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.612 × 10⁹⁹(100-digit number)
26125077951667910796…86840812438404149121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
5.225 × 10⁹⁹(100-digit number)
52250155903335821593…73681624876808298241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.045 × 10¹⁰⁰(101-digit number)
10450031180667164318…47363249753616596481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.090 × 10¹⁰⁰(101-digit number)
20900062361334328637…94726499507233192961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
4.180 × 10¹⁰⁰(101-digit number)
41800124722668657274…89452999014466385921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
8.360 × 10¹⁰⁰(101-digit number)
83600249445337314549…78905998028932771841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.672 × 10¹⁰¹(102-digit number)
16720049889067462909…57811996057865543681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
3.344 × 10¹⁰¹(102-digit number)
33440099778134925819…15623992115731087361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
6.688 × 10¹⁰¹(102-digit number)
66880199556269851639…31247984231462174721
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 10 consecutive prime numbers forming a Cunningham Chain of the Second Kind. The prime chain origin — the large number shown above — anchors the chain and is divisible by a primorial (the product of small primes), cryptographically tying these prime numbers to this specific block.

★★☆☆☆
Rarity
UncommonChain length 10

Roughly 1 in 100 blocks. Solid but expected in a healthy network.

How Primecoin's Proof-of-Work Constructs These Primes

Primecoin stores a value called the prime chain origin in each block. The miner found a large integer such that when divided by a primorial (the product of small primes: 2 × 3 × 5 × 7 × …), the result is the first prime in the chain. The origin is deliberately divisible by this primorial — that divisibility is part of the proof.

Prime Chain Origin = First Prime × Primorial (2·3·5·7·11·…)
Source: Primecoin prime.cpp — CheckPrimeProofOfWork()

This is why the origin has many small prime factors — those factors are the primorial divisor. The chain then extends from the first prime using the 2CC formula:

2CC: p₁ (first prime), p₂ = 2p₁ − 1, p₃ = 2p₂ − 1, …
Circulating Supply:57,706,864 XPM·at block #6,807,852 · updates every 60s
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