Block #322,489

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/21/2013, 1:16:37 AM · Difficulty 10.1920 · 6,495,283 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
e0dd48b25269e21147738dbf5501d3be0b83a2ec7724fd5930a5d5550f3ce3f9

Height

#322,489

Difficulty

10.192050

Transactions

6

Size

1.93 KB

Version

2

Bits

0a312a29

Nonce

64,787

Timestamp

12/21/2013, 1:16:37 AM

Confirmations

6,495,283

Merkle Root

55e84729b0a92f82ebc68a2b5ce0432d65ee5703acb2c68bd4df28f3cc289b42
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.

1.473 × 10⁹⁹(100-digit number)
14739592568427701116…28962591074802548801
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
1.473 × 10⁹⁹(100-digit number)
14739592568427701116…28962591074802548801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.947 × 10⁹⁹(100-digit number)
29479185136855402233…57925182149605097601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
5.895 × 10⁹⁹(100-digit number)
58958370273710804467…15850364299210195201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.179 × 10¹⁰⁰(101-digit number)
11791674054742160893…31700728598420390401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.358 × 10¹⁰⁰(101-digit number)
23583348109484321786…63401457196840780801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
4.716 × 10¹⁰⁰(101-digit number)
47166696218968643573…26802914393681561601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
9.433 × 10¹⁰⁰(101-digit number)
94333392437937287147…53605828787363123201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.886 × 10¹⁰¹(102-digit number)
18866678487587457429…07211657574726246401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
3.773 × 10¹⁰¹(102-digit number)
37733356975174914859…14423315149452492801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
7.546 × 10¹⁰¹(102-digit number)
75466713950349829718…28846630298904985601
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:57,786,233 XPM·at block #6,817,771 · updates every 60s
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