Block #369,424

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/21/2014, 9:53:56 AM · Difficulty 10.4447 · 6,447,541 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
3438bbe66b1aa236da9434c6f7315a41ce5514da2f1a2743791327539052154d

Height

#369,424

Difficulty

10.444738

Transactions

12

Size

16.29 KB

Version

2

Bits

0a71da54

Nonce

8,324

Timestamp

1/21/2014, 9:53:56 AM

Confirmations

6,447,541

Merkle Root

ffb78af444369f76daf9f94b6d54b868f1c74dbb037ba26fa9bcb46d8ae2e637
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.

1.133 × 10¹⁰¹(102-digit number)
11332101341359607520…05110719260625778401
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
1.133 × 10¹⁰¹(102-digit number)
11332101341359607520…05110719260625778401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.266 × 10¹⁰¹(102-digit number)
22664202682719215040…10221438521251556801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
4.532 × 10¹⁰¹(102-digit number)
45328405365438430080…20442877042503113601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
9.065 × 10¹⁰¹(102-digit number)
90656810730876860160…40885754085006227201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.813 × 10¹⁰²(103-digit number)
18131362146175372032…81771508170012454401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
3.626 × 10¹⁰²(103-digit number)
36262724292350744064…63543016340024908801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
7.252 × 10¹⁰²(103-digit number)
72525448584701488128…27086032680049817601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.450 × 10¹⁰³(104-digit number)
14505089716940297625…54172065360099635201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.901 × 10¹⁰³(104-digit number)
29010179433880595251…08344130720199270401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
5.802 × 10¹⁰³(104-digit number)
58020358867761190502…16688261440398540801
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:57,779,756 XPM·at block #6,816,964 · updates every 60s
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