Block #334,782

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/29/2013, 5:55:46 PM · Difficulty 10.1587 · 6,480,144 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
f7f65181c192716c638e4b58ff412430ce1b27ed7fec9bdbdbe8b710d343e169

Height

#334,782

Difficulty

10.158703

Transactions

12

Size

3.75 KB

Version

2

Bits

0a28a0c0

Nonce

11,010

Timestamp

12/29/2013, 5:55:46 PM

Confirmations

6,480,144

Merkle Root

7b96b539de01d664341811c54931dff3c7dc1fc105527d986935c0e445a34b96
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.

1.567 × 10⁹⁷(98-digit number)
15674167144059219960…08406556809686685901
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
1.567 × 10⁹⁷(98-digit number)
15674167144059219960…08406556809686685901
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
3.134 × 10⁹⁷(98-digit number)
31348334288118439920…16813113619373371801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
6.269 × 10⁹⁷(98-digit number)
62696668576236879841…33626227238746743601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.253 × 10⁹⁸(99-digit number)
12539333715247375968…67252454477493487201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.507 × 10⁹⁸(99-digit number)
25078667430494751936…34504908954986974401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
5.015 × 10⁹⁸(99-digit number)
50157334860989503873…69009817909973948801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.003 × 10⁹⁹(100-digit number)
10031466972197900774…38019635819947897601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.006 × 10⁹⁹(100-digit number)
20062933944395801549…76039271639895795201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
4.012 × 10⁹⁹(100-digit number)
40125867888791603098…52078543279791590401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
8.025 × 10⁹⁹(100-digit number)
80251735777583206197…04157086559583180801
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:57,763,502 XPM·at block #6,814,925 · updates every 60s
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