Block #322,818

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/21/2013, 6:49:30 AM · Difficulty 10.1919 · 6,469,801 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
448eaa44e920619a26e2c48f1fd9e4754c4ba921524b1514422fdead5c61f660

Height

#322,818

Difficulty

10.191881

Transactions

13

Size

4.80 KB

Version

2

Bits

0a311f17

Nonce

445,059

Timestamp

12/21/2013, 6:49:30 AM

Confirmations

6,469,801

Merkle Root

a60ddb7a7dde47d57d27a5f774fd006456fe1f7d71644af23d8d9ed5c1839ee1
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.

4.463 × 10⁹⁸(99-digit number)
44634992122445352747…21566384981938704801
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
4.463 × 10⁹⁸(99-digit number)
44634992122445352747…21566384981938704801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
8.926 × 10⁹⁸(99-digit number)
89269984244890705494…43132769963877409601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.785 × 10⁹⁹(100-digit number)
17853996848978141098…86265539927754819201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
3.570 × 10⁹⁹(100-digit number)
35707993697956282197…72531079855509638401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
7.141 × 10⁹⁹(100-digit number)
71415987395912564395…45062159711019276801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.428 × 10¹⁰⁰(101-digit number)
14283197479182512879…90124319422038553601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.856 × 10¹⁰⁰(101-digit number)
28566394958365025758…80248638844077107201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
5.713 × 10¹⁰⁰(101-digit number)
57132789916730051516…60497277688154214401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.142 × 10¹⁰¹(102-digit number)
11426557983346010303…20994555376308428801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.285 × 10¹⁰¹(102-digit number)
22853115966692020606…41989110752616857601
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:57,584,925 XPM·at block #6,792,618 · updates every 60s
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