1. #6,813,9442CC10 primes

    Cunningham 2nd · ⛏️ coinsforall.io

Block #364,213

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/17/2014, 10:20:41 PM · Difficulty 10.4200 · 6,449,732 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
80b9cbf0b2e4041ffad32933445e72d5c1ff2811b8feea4a5763124e8753cd7b

Height

#364,213

Difficulty

10.419990

Transactions

4

Size

1003 B

Version

2

Bits

0a6b8476

Nonce

236,295

Timestamp

1/17/2014, 10:20:41 PM

Confirmations

6,449,732

Merkle Root

1f561beeb00daceeb7bdfc364098a915570a5a32a35f14c7ec0f0ad397176644
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.

5.702 × 10⁹⁶(97-digit number)
57020338356816000237…04120870844969666401
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
5.702 × 10⁹⁶(97-digit number)
57020338356816000237…04120870844969666401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.140 × 10⁹⁷(98-digit number)
11404067671363200047…08241741689939332801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.280 × 10⁹⁷(98-digit number)
22808135342726400095…16483483379878665601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
4.561 × 10⁹⁷(98-digit number)
45616270685452800190…32966966759757331201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
9.123 × 10⁹⁷(98-digit number)
91232541370905600380…65933933519514662401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.824 × 10⁹⁸(99-digit number)
18246508274181120076…31867867039029324801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
3.649 × 10⁹⁸(99-digit number)
36493016548362240152…63735734078058649601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
7.298 × 10⁹⁸(99-digit number)
72986033096724480304…27471468156117299201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.459 × 10⁹⁹(100-digit number)
14597206619344896060…54942936312234598401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.919 × 10⁹⁹(100-digit number)
29194413238689792121…09885872624469196801
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:57,755,638 XPM·at block #6,813,944 · updates every 60s
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