Block #338,164

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/1/2014, 6:28:40 AM · Difficulty 10.1168 · 6,478,951 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
85ef3b05e774563522000dfd4445831022d92e3ca187d3aa1241f0bdc124e466

Height

#338,164

Difficulty

10.116823

Transactions

4

Size

6.30 KB

Version

2

Bits

0a1de819

Nonce

6,956

Timestamp

1/1/2014, 6:28:40 AM

Confirmations

6,478,951

Merkle Root

a678440c75eb6c1345c36199be99e0670edd72a52464f14c9f10c323feb9d90e
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.

2.236 × 10⁹⁸(99-digit number)
22367720952494271633…23299307473693423081
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
2.236 × 10⁹⁸(99-digit number)
22367720952494271633…23299307473693423081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
4.473 × 10⁹⁸(99-digit number)
44735441904988543267…46598614947386846161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
8.947 × 10⁹⁸(99-digit number)
89470883809977086534…93197229894773692321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.789 × 10⁹⁹(100-digit number)
17894176761995417306…86394459789547384641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
3.578 × 10⁹⁹(100-digit number)
35788353523990834613…72788919579094769281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
7.157 × 10⁹⁹(100-digit number)
71576707047981669227…45577839158189538561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.431 × 10¹⁰⁰(101-digit number)
14315341409596333845…91155678316379077121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.863 × 10¹⁰⁰(101-digit number)
28630682819192667691…82311356632758154241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
5.726 × 10¹⁰⁰(101-digit number)
57261365638385335382…64622713265516308481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.145 × 10¹⁰¹(102-digit number)
11452273127677067076…29245426531032616961
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:57,780,960 XPM·at block #6,817,114 · updates every 60s
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