Block #364,244

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/17/2014, 10:44:16 PM · Difficulty 10.4211 · 6,441,908 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
d9830730b99ee76d61fc309a57947929a29bc7b8fac43a8982b953b1804d7040

Height

#364,244

Difficulty

10.421147

Transactions

3

Size

651 B

Version

2

Bits

0a6bd043

Nonce

305,566

Timestamp

1/17/2014, 10:44:16 PM

Confirmations

6,441,908

Merkle Root

6d2b219da953d9d34af9e731fb3fc30ad39907077ec17cb30c6ddef8d41b5b6e
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.

1.030 × 10⁹⁷(98-digit number)
10303712457594312617…72151727753130485601
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
1.030 × 10⁹⁷(98-digit number)
10303712457594312617…72151727753130485601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.060 × 10⁹⁷(98-digit number)
20607424915188625234…44303455506260971201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
4.121 × 10⁹⁷(98-digit number)
41214849830377250468…88606911012521942401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
8.242 × 10⁹⁷(98-digit number)
82429699660754500936…77213822025043884801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.648 × 10⁹⁸(99-digit number)
16485939932150900187…54427644050087769601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
3.297 × 10⁹⁸(99-digit number)
32971879864301800374…08855288100175539201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
6.594 × 10⁹⁸(99-digit number)
65943759728603600748…17710576200351078401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.318 × 10⁹⁹(100-digit number)
13188751945720720149…35421152400702156801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.637 × 10⁹⁹(100-digit number)
26377503891441440299…70842304801404313601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
5.275 × 10⁹⁹(100-digit number)
52755007782882880599…41684609602808627201
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:57,693,296 XPM·at block #6,806,151 · updates every 60s
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