Block #382,191

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/30/2014, 12:47:49 PM · Difficulty 10.4054 · 6,414,554 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
18f70cd7403a766b2a682f40072708497108b96bd0b7fd30a9b86840fc94435c

Height

#382,191

Difficulty

10.405367

Transactions

3

Size

661 B

Version

2

Bits

0a67c628

Nonce

22,246

Timestamp

1/30/2014, 12:47:49 PM

Confirmations

6,414,554

Merkle Root

0adc08bd23470794d1fbfc4905991936bbf20f0e9c996a7029f96a16ae241648
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.

7.918 × 10⁹⁹(100-digit number)
79180290207226095843…96763881751765880321
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
7.918 × 10⁹⁹(100-digit number)
79180290207226095843…96763881751765880321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.583 × 10¹⁰⁰(101-digit number)
15836058041445219168…93527763503531760641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
3.167 × 10¹⁰⁰(101-digit number)
31672116082890438337…87055527007063521281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
6.334 × 10¹⁰⁰(101-digit number)
63344232165780876674…74111054014127042561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.266 × 10¹⁰¹(102-digit number)
12668846433156175334…48222108028254085121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.533 × 10¹⁰¹(102-digit number)
25337692866312350669…96444216056508170241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
5.067 × 10¹⁰¹(102-digit number)
50675385732624701339…92888432113016340481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.013 × 10¹⁰²(103-digit number)
10135077146524940267…85776864226032680961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.027 × 10¹⁰²(103-digit number)
20270154293049880535…71553728452065361921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
4.054 × 10¹⁰²(103-digit number)
40540308586099761071…43107456904130723841
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:57,617,969 XPM·at block #6,796,744 · updates every 60s
xpmprime.info is a work in progress. If you enjoy using this service you can support this project with a Primecoin donation.