Block #324,275

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/22/2013, 5:21:37 AM · Difficulty 10.2083 · 6,484,739 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
47fb1d3fe0d17ac9ebdf855a20c88faa55b771bb1460e36abaeba882f4d3a2bd

Height

#324,275

Difficulty

10.208323

Transactions

6

Size

1.30 KB

Version

2

Bits

0a3554ac

Nonce

35,605

Timestamp

12/22/2013, 5:21:37 AM

Confirmations

6,484,739

Merkle Root

bea6789a680a7798d91a35893934893dd9b1007eb8712324979658cfdb28e905
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.

1.824 × 10¹⁰⁰(101-digit number)
18246693772281747083…92212129048861151301
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
1.824 × 10¹⁰⁰(101-digit number)
18246693772281747083…92212129048861151301
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
3.649 × 10¹⁰⁰(101-digit number)
36493387544563494166…84424258097722302601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
7.298 × 10¹⁰⁰(101-digit number)
72986775089126988333…68848516195444605201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.459 × 10¹⁰¹(102-digit number)
14597355017825397666…37697032390889210401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.919 × 10¹⁰¹(102-digit number)
29194710035650795333…75394064781778420801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
5.838 × 10¹⁰¹(102-digit number)
58389420071301590666…50788129563556841601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.167 × 10¹⁰²(103-digit number)
11677884014260318133…01576259127113683201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.335 × 10¹⁰²(103-digit number)
23355768028520636266…03152518254227366401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
4.671 × 10¹⁰²(103-digit number)
46711536057041272533…06305036508454732801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
9.342 × 10¹⁰²(103-digit number)
93423072114082545066…12610073016909465601
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 10 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
UncommonChain length 10

Roughly 1 in 100 blocks. Solid but expected in a healthy network.

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:57,716,173 XPM·at block #6,809,013 · updates every 60s
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