Block #530,366

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 5/7/2014, 8:15:04 PM · Difficulty 10.8918 · 6,283,865 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
d66555482114cdc74e6578016d5dfb87753ae6c72757f6b80d89d9f3b2caa87d

Height

#530,366

Difficulty

10.891775

Transactions

5

Size

1.23 KB

Version

2

Bits

0ae44b65

Nonce

74,868,478

Timestamp

5/7/2014, 8:15:04 PM

Confirmations

6,283,865

Merkle Root

a238dd455b4dc3c1197b60b3cf5a985d37ca0c6547da6b48d7856265ac08b8d2
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.

6.671 × 10⁹⁸(99-digit number)
66716572460144374080…35542006035758715201
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
6.671 × 10⁹⁸(99-digit number)
66716572460144374080…35542006035758715201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.334 × 10⁹⁹(100-digit number)
13343314492028874816…71084012071517430401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.668 × 10⁹⁹(100-digit number)
26686628984057749632…42168024143034860801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
5.337 × 10⁹⁹(100-digit number)
53373257968115499264…84336048286069721601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.067 × 10¹⁰⁰(101-digit number)
10674651593623099852…68672096572139443201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.134 × 10¹⁰⁰(101-digit number)
21349303187246199705…37344193144278886401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
4.269 × 10¹⁰⁰(101-digit number)
42698606374492399411…74688386288557772801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
8.539 × 10¹⁰⁰(101-digit number)
85397212748984798823…49376772577115545601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.707 × 10¹⁰¹(102-digit number)
17079442549796959764…98753545154231091201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
3.415 × 10¹⁰¹(102-digit number)
34158885099593919529…97507090308462182401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
6.831 × 10¹⁰¹(102-digit number)
68317770199187839058…95014180616924364801
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 11 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
RareChain length 11

Approximately 1 in 1,000 blocks. Noteworthy discoveries.

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:57,757,919 XPM·at block #6,814,230 · updates every 60s
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