Block #327,738

1CCLength 10★★☆☆☆

Cunningham Chain of the First Kind · Discovered 12/24/2013, 6:48:39 PM · Difficulty 10.1731 · 6,475,966 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
e52f606470a60d732bd4794c0a78bd0ec90624d29184d70406c0ce178e4533c2

Height

#327,738

Difficulty

10.173129

Transactions

10

Size

4.18 KB

Version

2

Bits

0a2c5236

Nonce

205,497

Timestamp

12/24/2013, 6:48:39 PM

Confirmations

6,475,966

Merkle Root

cf194f2af76a624e6711789f0feccb2978f0a3ccb3795a1f5fabb4e6d8406607
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.

7.969 × 10⁹⁸(99-digit number)
79690025757473090797…55199251907658192199
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
7.969 × 10⁹⁸(99-digit number)
79690025757473090797…55199251907658192199
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
1.593 × 10⁹⁹(100-digit number)
15938005151494618159…10398503815316384399
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
3.187 × 10⁹⁹(100-digit number)
31876010302989236318…20797007630632768799
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
6.375 × 10⁹⁹(100-digit number)
63752020605978472637…41594015261265537599
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
1.275 × 10¹⁰⁰(101-digit number)
12750404121195694527…83188030522531075199
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
2.550 × 10¹⁰⁰(101-digit number)
25500808242391389055…66376061045062150399
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
5.100 × 10¹⁰⁰(101-digit number)
51001616484782778110…32752122090124300799
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
1.020 × 10¹⁰¹(102-digit number)
10200323296956555622…65504244180248601599
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
2.040 × 10¹⁰¹(102-digit number)
20400646593913111244…31008488360497203199
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
4.080 × 10¹⁰¹(102-digit number)
40801293187826222488…62016976720994406399
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:57,673,671 XPM·at block #6,803,703 · updates every 60s
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