Block #301,414

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/9/2013, 4:32:50 AM · Difficulty 9.9925 · 6,508,028 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
3c0b35360afa639356bf5e6f04a8b8e845ba8bd04779fc7c485b7634bcbf2e7a

Height

#301,414

Difficulty

9.992519

Transactions

23

Size

5.42 KB

Version

2

Bits

09fe15b6

Nonce

248,571

Timestamp

12/9/2013, 4:32:50 AM

Confirmations

6,508,028

Merkle Root

0229ebb94558c64a18af68f32b1a69e7fc0370b7f5d797e5f1c4207c4fedb1e9
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.

5.321 × 10⁹¹(92-digit number)
53211167252384810153…76837528432218433921
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
5.321 × 10⁹¹(92-digit number)
53211167252384810153…76837528432218433921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.064 × 10⁹²(93-digit number)
10642233450476962030…53675056864436867841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.128 × 10⁹²(93-digit number)
21284466900953924061…07350113728873735681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
4.256 × 10⁹²(93-digit number)
42568933801907848122…14700227457747471361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
8.513 × 10⁹²(93-digit number)
85137867603815696245…29400454915494942721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.702 × 10⁹³(94-digit number)
17027573520763139249…58800909830989885441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
3.405 × 10⁹³(94-digit number)
34055147041526278498…17601819661979770881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
6.811 × 10⁹³(94-digit number)
68110294083052556996…35203639323959541761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.362 × 10⁹⁴(95-digit number)
13622058816610511399…70407278647919083521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.724 × 10⁹⁴(95-digit number)
27244117633221022798…40814557295838167041
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:57,719,606 XPM·at block #6,809,441 · updates every 60s
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