Block #379,882

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/28/2014, 8:06:38 PM · Difficulty 10.4202 · 6,430,305 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
2042b1247552875924712698b54a7a017a89ae22858041608fdd07729aa780ad

Height

#379,882

Difficulty

10.420184

Transactions

2

Size

1.67 KB

Version

2

Bits

0a6b9126

Nonce

185,279

Timestamp

1/28/2014, 8:06:38 PM

Confirmations

6,430,305

Merkle Root

4164e8a727cf947afa17a008e8f111839793109cc2e3c4afce619266f6ac58c3
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.

4.731 × 10⁹⁴(95-digit number)
47310133283215691552…79130694707299433921
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
4.731 × 10⁹⁴(95-digit number)
47310133283215691552…79130694707299433921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
9.462 × 10⁹⁴(95-digit number)
94620266566431383105…58261389414598867841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.892 × 10⁹⁵(96-digit number)
18924053313286276621…16522778829197735681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
3.784 × 10⁹⁵(96-digit number)
37848106626572553242…33045557658395471361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
7.569 × 10⁹⁵(96-digit number)
75696213253145106484…66091115316790942721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.513 × 10⁹⁶(97-digit number)
15139242650629021296…32182230633581885441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
3.027 × 10⁹⁶(97-digit number)
30278485301258042593…64364461267163770881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
6.055 × 10⁹⁶(97-digit number)
60556970602516085187…28728922534327541761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.211 × 10⁹⁷(98-digit number)
12111394120503217037…57457845068655083521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.422 × 10⁹⁷(98-digit number)
24222788241006434075…14915690137310167041
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:57,725,566 XPM·at block #6,810,186 · updates every 60s
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