Block #327,508

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/24/2013, 2:38:41 PM · Difficulty 10.1767 · 6,467,038 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
1932d4adaf880494ead62049f9d51ec59d0c66f0035a4d5529c81bc59483e5c6

Height

#327,508

Difficulty

10.176656

Transactions

13

Size

10.82 KB

Version

2

Bits

0a2d394d

Nonce

386,299

Timestamp

12/24/2013, 2:38:41 PM

Confirmations

6,467,038

Merkle Root

0ff2e593ac21d05a5a5ae39017ed6367cdb6ec97393ad5c52d4765ae84b93fff
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.

1.026 × 10¹⁰¹(102-digit number)
10267773569841884429…32425873259946196801
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
1.026 × 10¹⁰¹(102-digit number)
10267773569841884429…32425873259946196801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.053 × 10¹⁰¹(102-digit number)
20535547139683768859…64851746519892393601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
4.107 × 10¹⁰¹(102-digit number)
41071094279367537719…29703493039784787201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
8.214 × 10¹⁰¹(102-digit number)
82142188558735075439…59406986079569574401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.642 × 10¹⁰²(103-digit number)
16428437711747015087…18813972159139148801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
3.285 × 10¹⁰²(103-digit number)
32856875423494030175…37627944318278297601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
6.571 × 10¹⁰²(103-digit number)
65713750846988060351…75255888636556595201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.314 × 10¹⁰³(104-digit number)
13142750169397612070…50511777273113190401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.628 × 10¹⁰³(104-digit number)
26285500338795224140…01023554546226380801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
5.257 × 10¹⁰³(104-digit number)
52571000677590448281…02047109092452761601
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:57,600,408 XPM·at block #6,794,545 · updates every 60s
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