Block #437,175

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 3/10/2014, 3:07:03 AM · Difficulty 10.3578 · 6,370,998 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
96f1183094553d17cb00063fe9510948a66165f73eded33a1465c4aad6ff9726

Height

#437,175

Difficulty

10.357753

Transactions

1

Size

1.01 KB

Version

2

Bits

0a5b95ab

Nonce

1,039

Timestamp

3/10/2014, 3:07:03 AM

Confirmations

6,370,998

Merkle Root

2a1f71648e7a1fc5aae7a1e80f4116d11dad76db03eb1b7fbb1ae3cd3031d686
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.

7.910 × 10⁹⁴(95-digit number)
79107240815425098530…02341981763301800981
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
7.910 × 10⁹⁴(95-digit number)
79107240815425098530…02341981763301800981
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.582 × 10⁹⁵(96-digit number)
15821448163085019706…04683963526603601961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
3.164 × 10⁹⁵(96-digit number)
31642896326170039412…09367927053207203921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
6.328 × 10⁹⁵(96-digit number)
63285792652340078824…18735854106414407841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.265 × 10⁹⁶(97-digit number)
12657158530468015764…37471708212828815681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.531 × 10⁹⁶(97-digit number)
25314317060936031529…74943416425657631361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
5.062 × 10⁹⁶(97-digit number)
50628634121872063059…49886832851315262721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.012 × 10⁹⁷(98-digit number)
10125726824374412611…99773665702630525441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.025 × 10⁹⁷(98-digit number)
20251453648748825223…99547331405261050881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
4.050 × 10⁹⁷(98-digit number)
40502907297497650447…99094662810522101761
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:57,709,431 XPM·at block #6,808,172 · updates every 60s
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