Block #324,687

1CCLength 10★★☆☆☆

Cunningham Chain of the First Kind · Discovered 12/22/2013, 12:23:43 PM · Difficulty 10.2067 · 6,500,814 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
b206371693b6a7b0e1d04a3eb3a9d624669041f928bc87185c584cb784acc8a6

Height

#324,687

Difficulty

10.206747

Transactions

1

Size

1.05 KB

Version

2

Bits

0a34ed5d

Nonce

121,613

Timestamp

12/22/2013, 12:23:43 PM

Confirmations

6,500,814

Merkle Root

d9bdd7ddeea4cadbc5fc47fcf4dec55a9e52609cb39920ff5c95b6182cefb93a
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.

1.040 × 10⁹⁹(100-digit number)
10406460271360538839…98574624392435404799
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
1.040 × 10⁹⁹(100-digit number)
10406460271360538839…98574624392435404799
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
2.081 × 10⁹⁹(100-digit number)
20812920542721077678…97149248784870809599
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
4.162 × 10⁹⁹(100-digit number)
41625841085442155356…94298497569741619199
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
8.325 × 10⁹⁹(100-digit number)
83251682170884310712…88596995139483238399
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
1.665 × 10¹⁰⁰(101-digit number)
16650336434176862142…77193990278966476799
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
3.330 × 10¹⁰⁰(101-digit number)
33300672868353724285…54387980557932953599
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
6.660 × 10¹⁰⁰(101-digit number)
66601345736707448570…08775961115865907199
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
1.332 × 10¹⁰¹(102-digit number)
13320269147341489714…17551922231731814399
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
2.664 × 10¹⁰¹(102-digit number)
26640538294682979428…35103844463463628799
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
5.328 × 10¹⁰¹(102-digit number)
53281076589365958856…70207688926927257599
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 First 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 1CC formula:

1CC: p₁ (first prime), p₂ = 2p₁ + 1, p₃ = 2p₂ + 1, …
Circulating Supply:57,848,105 XPM·at block #6,825,500 · updates every 60s
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