Block #2,595,497

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 4/1/2018, 2:26:22 PM · Difficulty 11.2974 · 4,237,787 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
ee2fcbe764d343dd60878be1ec8f5c56ea5f5656b2598faff74e3845eb98955f

Height

#2,595,497

Difficulty

11.297435

Transactions

2

Size

426 B

Version

2

Bits

0b4c24ba

Nonce

2,098,737,944

Timestamp

4/1/2018, 2:26:22 PM

Confirmations

4,237,787

Merkle Root

59af716d9476972167e30ad2649d6e5a678910a9edeb45132e279ba1659aa771
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.

8.435 × 10⁹⁶(97-digit number)
84357404092377561969…05939764935210086401
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
8.435 × 10⁹⁶(97-digit number)
84357404092377561969…05939764935210086401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.687 × 10⁹⁷(98-digit number)
16871480818475512393…11879529870420172801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
3.374 × 10⁹⁷(98-digit number)
33742961636951024787…23759059740840345601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
6.748 × 10⁹⁷(98-digit number)
67485923273902049575…47518119481680691201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.349 × 10⁹⁸(99-digit number)
13497184654780409915…95036238963361382401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.699 × 10⁹⁸(99-digit number)
26994369309560819830…90072477926722764801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
5.398 × 10⁹⁸(99-digit number)
53988738619121639660…80144955853445529601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.079 × 10⁹⁹(100-digit number)
10797747723824327932…60289911706891059201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.159 × 10⁹⁹(100-digit number)
21595495447648655864…20579823413782118401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
4.319 × 10⁹⁹(100-digit number)
43190990895297311728…41159646827564236801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
8.638 × 10⁹⁹(100-digit number)
86381981790594623456…82319293655128473601
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:57,910,459 XPM·at block #6,833,283 · updates every 60s
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