Block #752,053

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 10/4/2014, 11:30:12 AM · Difficulty 10.9735 · 6,051,730 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
4060c5e9e14e75d82ee42ad7d4beca2aa698c519178310c2e48a48f14ffcba59

Height

#752,053

Difficulty

10.973519

Transactions

5

Size

1.23 KB

Version

2

Bits

0af9388a

Nonce

40,213,545

Timestamp

10/4/2014, 11:30:12 AM

Confirmations

6,051,730

Merkle Root

7855fecb7525c077daf8769c930c8c83a4fa0466176a672c43e517f459d40a2c
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.

6.798 × 10⁹⁶(97-digit number)
67981254437746002487…54304817737994312801
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
6.798 × 10⁹⁶(97-digit number)
67981254437746002487…54304817737994312801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.359 × 10⁹⁷(98-digit number)
13596250887549200497…08609635475988625601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.719 × 10⁹⁷(98-digit number)
27192501775098400994…17219270951977251201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
5.438 × 10⁹⁷(98-digit number)
54385003550196801989…34438541903954502401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.087 × 10⁹⁸(99-digit number)
10877000710039360397…68877083807909004801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.175 × 10⁹⁸(99-digit number)
21754001420078720795…37754167615818009601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
4.350 × 10⁹⁸(99-digit number)
43508002840157441591…75508335231636019201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
8.701 × 10⁹⁸(99-digit number)
87016005680314883183…51016670463272038401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.740 × 10⁹⁹(100-digit number)
17403201136062976636…02033340926544076801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
3.480 × 10⁹⁹(100-digit number)
34806402272125953273…04066681853088153601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
6.961 × 10⁹⁹(100-digit number)
69612804544251906546…08133363706176307201
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:57,674,296 XPM·at block #6,803,781 · updates every 60s
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