Block #2,679,775

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 5/27/2018, 6:22:47 AM · Difficulty 11.6920 · 4,145,222 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
8fa5c3d696ca72dd9a3bad20d73258b4efdb0dc6c3c08a190092d06bb9c832bb

Height

#2,679,775

Difficulty

11.692047

Transactions

2

Size

574 B

Version

2

Bits

0bb12a02

Nonce

278,515,975

Timestamp

5/27/2018, 6:22:47 AM

Confirmations

4,145,222

Merkle Root

2992c54f3b51a2b369993dbf532018c27e4b7830b902517a056ad209593b9051
Transactions (2)
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.

2.623 × 10⁹⁶(97-digit number)
26239342387083078045…68637643750865799681
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
2.623 × 10⁹⁶(97-digit number)
26239342387083078045…68637643750865799681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
5.247 × 10⁹⁶(97-digit number)
52478684774166156091…37275287501731599361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.049 × 10⁹⁷(98-digit number)
10495736954833231218…74550575003463198721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.099 × 10⁹⁷(98-digit number)
20991473909666462436…49101150006926397441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
4.198 × 10⁹⁷(98-digit number)
41982947819332924873…98202300013852794881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
8.396 × 10⁹⁷(98-digit number)
83965895638665849746…96404600027705589761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.679 × 10⁹⁸(99-digit number)
16793179127733169949…92809200055411179521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
3.358 × 10⁹⁸(99-digit number)
33586358255466339898…85618400110822359041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
6.717 × 10⁹⁸(99-digit number)
67172716510932679796…71236800221644718081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.343 × 10⁹⁹(100-digit number)
13434543302186535959…42473600443289436161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
2.686 × 10⁹⁹(100-digit number)
26869086604373071918…84947200886578872321
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:57,844,058 XPM·at block #6,824,996 · updates every 60s
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