Block #350,094

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/8/2014, 7:26:08 PM · Difficulty 10.2892 · 6,453,233 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
2b5ad34c1e4e7a6ea15dd2e428f6b128caccad0c0d9aade01e35fddaf28f5cac

Height

#350,094

Difficulty

10.289204

Transactions

22

Size

4.98 KB

Version

2

Bits

0a4a0945

Nonce

70,824

Timestamp

1/8/2014, 7:26:08 PM

Confirmations

6,453,233

Merkle Root

f17c005084700ce2e4954b5667d1e408f934956a6c50de1b55b8c0303533f0f9
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.

5.312 × 10⁹³(94-digit number)
53126163727097961071…98633444417003888951
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
5.312 × 10⁹³(94-digit number)
53126163727097961071…98633444417003888951
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.062 × 10⁹⁴(95-digit number)
10625232745419592214…97266888834007777901
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.125 × 10⁹⁴(95-digit number)
21250465490839184428…94533777668015555801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
4.250 × 10⁹⁴(95-digit number)
42500930981678368857…89067555336031111601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
8.500 × 10⁹⁴(95-digit number)
85001861963356737714…78135110672062223201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.700 × 10⁹⁵(96-digit number)
17000372392671347542…56270221344124446401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
3.400 × 10⁹⁵(96-digit number)
34000744785342695085…12540442688248892801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
6.800 × 10⁹⁵(96-digit number)
68001489570685390171…25080885376497785601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.360 × 10⁹⁶(97-digit number)
13600297914137078034…50161770752995571201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.720 × 10⁹⁶(97-digit number)
27200595828274156068…00323541505991142401
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:57,670,647 XPM·at block #6,803,326 · updates every 60s
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