Block #310,789

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/14/2013, 6:03:29 AM · Difficulty 9.9953 · 6,481,442 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
15e3eca70f10c610ceac304214ce080ffc24479c79c156562530f626779a835a

Height

#310,789

Difficulty

9.995289

Transactions

17

Size

4.33 KB

Version

2

Bits

09fecb3b

Nonce

72,641

Timestamp

12/14/2013, 6:03:29 AM

Confirmations

6,481,442

Merkle Root

01a9f69cb29ab5427e810022fb74320b0fc0a242f5d34839495386c8ff733392
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.

5.326 × 10⁹⁴(95-digit number)
53262679624527957459…19819322646275039001
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
5.326 × 10⁹⁴(95-digit number)
53262679624527957459…19819322646275039001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.065 × 10⁹⁵(96-digit number)
10652535924905591491…39638645292550078001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.130 × 10⁹⁵(96-digit number)
21305071849811182983…79277290585100156001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
4.261 × 10⁹⁵(96-digit number)
42610143699622365967…58554581170200312001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
8.522 × 10⁹⁵(96-digit number)
85220287399244731935…17109162340400624001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.704 × 10⁹⁶(97-digit number)
17044057479848946387…34218324680801248001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
3.408 × 10⁹⁶(97-digit number)
34088114959697892774…68436649361602496001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
6.817 × 10⁹⁶(97-digit number)
68176229919395785548…36873298723204992001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.363 × 10⁹⁷(98-digit number)
13635245983879157109…73746597446409984001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.727 × 10⁹⁷(98-digit number)
27270491967758314219…47493194892819968001
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:57,581,805 XPM·at block #6,792,230 · updates every 60s
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