Block #330,982

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/27/2013, 1:25:13 AM · Difficulty 10.1684 · 6,468,376 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
5d65b215b1552545937d5a276cde08e42b8d7d072d0e712bc9ede44fe681f548

Height

#330,982

Difficulty

10.168413

Transactions

9

Size

2.81 KB

Version

2

Bits

0a2b1d1c

Nonce

6,781

Timestamp

12/27/2013, 1:25:13 AM

Confirmations

6,468,376

Merkle Root

9849ed2e959cb785f9de9b586235580a2a1df2ee2aa36abbb971de5204c8c53d
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.

3.926 × 10¹⁰³(104-digit number)
39265845750804078108…54448412290240596801
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
3.926 × 10¹⁰³(104-digit number)
39265845750804078108…54448412290240596801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
7.853 × 10¹⁰³(104-digit number)
78531691501608156216…08896824580481193601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.570 × 10¹⁰⁴(105-digit number)
15706338300321631243…17793649160962387201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
3.141 × 10¹⁰⁴(105-digit number)
31412676600643262486…35587298321924774401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
6.282 × 10¹⁰⁴(105-digit number)
62825353201286524973…71174596643849548801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.256 × 10¹⁰⁵(106-digit number)
12565070640257304994…42349193287699097601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.513 × 10¹⁰⁵(106-digit number)
25130141280514609989…84698386575398195201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
5.026 × 10¹⁰⁵(106-digit number)
50260282561029219978…69396773150796390401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.005 × 10¹⁰⁶(107-digit number)
10052056512205843995…38793546301592780801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.010 × 10¹⁰⁶(107-digit number)
20104113024411687991…77587092603185561601
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:57,638,910 XPM·at block #6,799,357 · updates every 60s
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