Block #2,767,597

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 7/27/2018, 1:38:00 PM · Difficulty 11.6660 · 4,069,872 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
52e1ad3ce123ebfb5c10ab0adb033aa1bde4edb63a08a85b2f63ce86f6cc2498

Height

#2,767,597

Difficulty

11.666033

Transactions

14

Size

3.84 KB

Version

2

Bits

0baa812a

Nonce

1,313,508,444

Timestamp

7/27/2018, 1:38:00 PM

Confirmations

4,069,872

Merkle Root

706ff5b6ebbcb7f17570281c278ec742ae702600a45ef6eab1ff0898db0afe3d
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.

4.262 × 10⁹⁵(96-digit number)
42625426714772976480…98820660232558958401
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
4.262 × 10⁹⁵(96-digit number)
42625426714772976480…98820660232558958401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
8.525 × 10⁹⁵(96-digit number)
85250853429545952961…97641320465117916801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.705 × 10⁹⁶(97-digit number)
17050170685909190592…95282640930235833601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
3.410 × 10⁹⁶(97-digit number)
34100341371818381184…90565281860471667201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
6.820 × 10⁹⁶(97-digit number)
68200682743636762368…81130563720943334401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.364 × 10⁹⁷(98-digit number)
13640136548727352473…62261127441886668801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.728 × 10⁹⁷(98-digit number)
27280273097454704947…24522254883773337601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
5.456 × 10⁹⁷(98-digit number)
54560546194909409895…49044509767546675201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.091 × 10⁹⁸(99-digit number)
10912109238981881979…98089019535093350401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.182 × 10⁹⁸(99-digit number)
21824218477963763958…96178039070186700801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
4.364 × 10⁹⁸(99-digit number)
43648436955927527916…92356078140373401601
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:57,944,072 XPM·at block #6,837,468 · updates every 60s
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