Block #879,411

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 1/2/2015, 3:57:09 PM · Difficulty 10.9626 · 5,930,577 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
6fcb303df807eeab14e5bac6517429d298e1653999a6c894e2eac58a0f68e010

Height

#879,411

Difficulty

10.962611

Transactions

4

Size

1.11 KB

Version

2

Bits

0af66da6

Nonce

397,062,489

Timestamp

1/2/2015, 3:57:09 PM

Confirmations

5,930,577

Merkle Root

fd671699709943cb4025bc710859a62e99ad5370c5bbf4c174caedf7ecc3e23c
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.

1.100 × 10⁹⁶(97-digit number)
11008659407465033523…87591229970032354561
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
1.100 × 10⁹⁶(97-digit number)
11008659407465033523…87591229970032354561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.201 × 10⁹⁶(97-digit number)
22017318814930067046…75182459940064709121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
4.403 × 10⁹⁶(97-digit number)
44034637629860134093…50364919880129418241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
8.806 × 10⁹⁶(97-digit number)
88069275259720268187…00729839760258836481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.761 × 10⁹⁷(98-digit number)
17613855051944053637…01459679520517672961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
3.522 × 10⁹⁷(98-digit number)
35227710103888107274…02919359041035345921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
7.045 × 10⁹⁷(98-digit number)
70455420207776214549…05838718082070691841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.409 × 10⁹⁸(99-digit number)
14091084041555242909…11677436164141383681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.818 × 10⁹⁸(99-digit number)
28182168083110485819…23354872328282767361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
5.636 × 10⁹⁸(99-digit number)
56364336166220971639…46709744656565534721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
1.127 × 10⁹⁹(100-digit number)
11272867233244194327…93419489313131069441
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 11 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
RareChain length 11

Approximately 1 in 1,000 blocks. Noteworthy discoveries.

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:57,723,977 XPM·at block #6,809,987 · updates every 60s
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