Block #322,318

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/20/2013, 10:09:34 PM · Difficulty 10.1945 · 6,481,888 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
4383ba15b28dd5ef00d7104b9c8e4530a3a1ff85db1e51525231f8a9190e32a1

Height

#322,318

Difficulty

10.194497

Transactions

19

Size

6.77 KB

Version

2

Bits

0a31ca92

Nonce

53,621

Timestamp

12/20/2013, 10:09:34 PM

Confirmations

6,481,888

Merkle Root

609e4f15854a43eeec4a087699f8758555ac52c69658af0c1784b0c32fc07373
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 × 10⁹⁷(98-digit number)
44631650418722632188…48130681470350963681
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 × 10⁹⁷(98-digit number)
44631650418722632188…48130681470350963681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
8.926 × 10⁹⁷(98-digit number)
89263300837445264377…96261362940701927361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.785 × 10⁹⁸(99-digit number)
17852660167489052875…92522725881403854721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
3.570 × 10⁹⁸(99-digit number)
35705320334978105751…85045451762807709441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
7.141 × 10⁹⁸(99-digit number)
71410640669956211502…70090903525615418881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.428 × 10⁹⁹(100-digit number)
14282128133991242300…40181807051230837761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.856 × 10⁹⁹(100-digit number)
28564256267982484600…80363614102461675521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
5.712 × 10⁹⁹(100-digit number)
57128512535964969201…60727228204923351041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.142 × 10¹⁰⁰(101-digit number)
11425702507192993840…21454456409846702081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.285 × 10¹⁰⁰(101-digit number)
22851405014385987680…42908912819693404161
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:57,677,696 XPM·at block #6,804,205 · updates every 60s
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