Block #372,327

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/23/2014, 12:53:11 PM · Difficulty 10.4271 · 6,435,702 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
3718f04ec92bbac0520472cd38d1827e724eee6313dbc5f74c4b1d0cca560319

Height

#372,327

Difficulty

10.427145

Transactions

2

Size

1.17 KB

Version

2

Bits

0a6d595d

Nonce

67,949

Timestamp

1/23/2014, 12:53:11 PM

Confirmations

6,435,702

Merkle Root

5454b05d2ea851dba6f36d5b127a50ca8b7f1434824a49dc36d25248e5d7e7c4
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.

9.591 × 10⁹¹(92-digit number)
95911065390848850452…92073696927945856501
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
9.591 × 10⁹¹(92-digit number)
95911065390848850452…92073696927945856501
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.918 × 10⁹²(93-digit number)
19182213078169770090…84147393855891713001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
3.836 × 10⁹²(93-digit number)
38364426156339540181…68294787711783426001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
7.672 × 10⁹²(93-digit number)
76728852312679080362…36589575423566852001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.534 × 10⁹³(94-digit number)
15345770462535816072…73179150847133704001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
3.069 × 10⁹³(94-digit number)
30691540925071632144…46358301694267408001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
6.138 × 10⁹³(94-digit number)
61383081850143264289…92716603388534816001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.227 × 10⁹⁴(95-digit number)
12276616370028652857…85433206777069632001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.455 × 10⁹⁴(95-digit number)
24553232740057305715…70866413554139264001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
4.910 × 10⁹⁴(95-digit number)
49106465480114611431…41732827108278528001
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:57,708,276 XPM·at block #6,808,028 · updates every 60s
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