Block #364,741

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/18/2014, 6:55:53 AM · Difficulty 10.4218 · 6,443,450 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
4e22bcaa8b26bede3bd4199d08b5e6ce566480871654cd9d1e14a266e0249fbc

Height

#364,741

Difficulty

10.421831

Transactions

2

Size

1.10 KB

Version

2

Bits

0a6bfd24

Nonce

318,174

Timestamp

1/18/2014, 6:55:53 AM

Confirmations

6,443,450

Merkle Root

feed5356b5bf2b45cfa5f52b8849848f983a518b534069144e6b05f61df370cd
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.

5.644 × 10⁹⁷(98-digit number)
56449181558893451290…51893944688397260801
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
5.644 × 10⁹⁷(98-digit number)
56449181558893451290…51893944688397260801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.128 × 10⁹⁸(99-digit number)
11289836311778690258…03787889376794521601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.257 × 10⁹⁸(99-digit number)
22579672623557380516…07575778753589043201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
4.515 × 10⁹⁸(99-digit number)
45159345247114761032…15151557507178086401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
9.031 × 10⁹⁸(99-digit number)
90318690494229522065…30303115014356172801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.806 × 10⁹⁹(100-digit number)
18063738098845904413…60606230028712345601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
3.612 × 10⁹⁹(100-digit number)
36127476197691808826…21212460057424691201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
7.225 × 10⁹⁹(100-digit number)
72254952395383617652…42424920114849382401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.445 × 10¹⁰⁰(101-digit number)
14450990479076723530…84849840229698764801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.890 × 10¹⁰⁰(101-digit number)
28901980958153447060…69699680459397529601
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:57,709,579 XPM·at block #6,808,190 · updates every 60s
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