Block #2,934,627

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 11/22/2018, 5:00:41 PM · Difficulty 11.3933 · 3,908,493 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
570d1b8897c17652c026d5e8df91f3b187fd1ac1307906e2c3ea202c54767d13

Height

#2,934,627

Difficulty

11.393267

Transactions

2

Size

1.14 KB

Version

2

Bits

0b64ad29

Nonce

535,613,000

Timestamp

11/22/2018, 5:00:41 PM

Confirmations

3,908,493

Merkle Root

f815827918bbae0a013f67bfa87017d36a19ca2f66916c247076ae8dffc75655
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.

1.557 × 10⁹⁴(95-digit number)
15579290846981094811…45207556252165034921
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
1.557 × 10⁹⁴(95-digit number)
15579290846981094811…45207556252165034921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
3.115 × 10⁹⁴(95-digit number)
31158581693962189623…90415112504330069841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
6.231 × 10⁹⁴(95-digit number)
62317163387924379247…80830225008660139681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.246 × 10⁹⁵(96-digit number)
12463432677584875849…61660450017320279361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.492 × 10⁹⁵(96-digit number)
24926865355169751698…23320900034640558721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
4.985 × 10⁹⁵(96-digit number)
49853730710339503397…46641800069281117441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
9.970 × 10⁹⁵(96-digit number)
99707461420679006795…93283600138562234881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.994 × 10⁹⁶(97-digit number)
19941492284135801359…86567200277124469761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
3.988 × 10⁹⁶(97-digit number)
39882984568271602718…73134400554248939521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
7.976 × 10⁹⁶(97-digit number)
79765969136543205436…46268801108497879041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
1.595 × 10⁹⁷(98-digit number)
15953193827308641087…92537602216995758081
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:57,989,325 XPM·at block #6,843,119 · updates every 60s
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