Block #330,329

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/26/2013, 2:38:37 PM · Difficulty 10.1677 · 6,477,887 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
7d9a2c8544844cdbc5cde209b9ad334df19cc640d3aaddc74df31f5f619e1505

Height

#330,329

Difficulty

10.167719

Transactions

9

Size

1.90 KB

Version

2

Bits

0a2aefaa

Nonce

271,627

Timestamp

12/26/2013, 2:38:37 PM

Confirmations

6,477,887

Merkle Root

4d24674754315ed031659c3259ebe8e370e35e085170dda08bb7d09b8779b79b
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.

2.526 × 10⁹⁹(100-digit number)
25261916592855462170…59707741539236773121
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
2.526 × 10⁹⁹(100-digit number)
25261916592855462170…59707741539236773121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
5.052 × 10⁹⁹(100-digit number)
50523833185710924340…19415483078473546241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.010 × 10¹⁰⁰(101-digit number)
10104766637142184868…38830966156947092481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.020 × 10¹⁰⁰(101-digit number)
20209533274284369736…77661932313894184961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
4.041 × 10¹⁰⁰(101-digit number)
40419066548568739472…55323864627788369921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
8.083 × 10¹⁰⁰(101-digit number)
80838133097137478944…10647729255576739841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.616 × 10¹⁰¹(102-digit number)
16167626619427495788…21295458511153479681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
3.233 × 10¹⁰¹(102-digit number)
32335253238854991577…42590917022306959361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
6.467 × 10¹⁰¹(102-digit number)
64670506477709983155…85181834044613918721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.293 × 10¹⁰²(103-digit number)
12934101295541996631…70363668089227837441
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:57,709,780 XPM·at block #6,808,215 · updates every 60s
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