Block #324,299

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/22/2013, 5:52:38 AM · Difficulty 10.2075 · 6,475,056 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
bef9d4e3af54f0700c9c052edea5889b612e40ece9fc63be00081b37425da60f

Height

#324,299

Difficulty

10.207474

Transactions

4

Size

1.64 KB

Version

2

Bits

0a351d03

Nonce

383,884

Timestamp

12/22/2013, 5:52:38 AM

Confirmations

6,475,056

Merkle Root

f03e44554042f6a4980b26cb98689517ea37c324da9eba9d8a94ec2c0ab99392
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.

1.209 × 10⁹⁷(98-digit number)
12099253284892878383…79472505886561703921
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
1.209 × 10⁹⁷(98-digit number)
12099253284892878383…79472505886561703921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.419 × 10⁹⁷(98-digit number)
24198506569785756767…58945011773123407841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
4.839 × 10⁹⁷(98-digit number)
48397013139571513534…17890023546246815681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
9.679 × 10⁹⁷(98-digit number)
96794026279143027068…35780047092493631361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.935 × 10⁹⁸(99-digit number)
19358805255828605413…71560094184987262721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
3.871 × 10⁹⁸(99-digit number)
38717610511657210827…43120188369974525441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
7.743 × 10⁹⁸(99-digit number)
77435221023314421654…86240376739949050881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.548 × 10⁹⁹(100-digit number)
15487044204662884330…72480753479898101761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
3.097 × 10⁹⁹(100-digit number)
30974088409325768661…44961506959796203521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
6.194 × 10⁹⁹(100-digit number)
61948176818651537323…89923013919592407041
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:57,638,885 XPM·at block #6,799,354 · updates every 60s
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