Block #329,228

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/25/2013, 7:45:20 PM · Difficulty 10.1727 · 6,481,734 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
6acd7d54caa3022c492807f55757274d6abeb3a19b703002ab333276dc867cb7

Height

#329,228

Difficulty

10.172700

Transactions

3

Size

2.00 KB

Version

2

Bits

0a2c3619

Nonce

46,549

Timestamp

12/25/2013, 7:45:20 PM

Confirmations

6,481,734

Merkle Root

ae0b622ab609c551904690c29f70d899f9b916fe9b0ab8af6d1b443a92a50850
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.

2.691 × 10⁹⁸(99-digit number)
26918468091382084565…07971821386620576001
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
2.691 × 10⁹⁸(99-digit number)
26918468091382084565…07971821386620576001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
5.383 × 10⁹⁸(99-digit number)
53836936182764169130…15943642773241152001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.076 × 10⁹⁹(100-digit number)
10767387236552833826…31887285546482304001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.153 × 10⁹⁹(100-digit number)
21534774473105667652…63774571092964608001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
4.306 × 10⁹⁹(100-digit number)
43069548946211335304…27549142185929216001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
8.613 × 10⁹⁹(100-digit number)
86139097892422670608…55098284371858432001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.722 × 10¹⁰⁰(101-digit number)
17227819578484534121…10196568743716864001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
3.445 × 10¹⁰⁰(101-digit number)
34455639156969068243…20393137487433728001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
6.891 × 10¹⁰⁰(101-digit number)
68911278313938136486…40786274974867456001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.378 × 10¹⁰¹(102-digit number)
13782255662787627297…81572549949734912001
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:57,731,797 XPM·at block #6,810,961 · updates every 60s
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