Block #226,189

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 10/25/2013, 1:10:22 AM · Difficulty 9.9362 · 6,580,176 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
1701b890510c558c39c6abf008c457bc99357d52c313acf11c3d10c7d4dafda2

Height

#226,189

Difficulty

9.936155

Transactions

6

Size

1.49 KB

Version

2

Bits

09efa7dc

Nonce

46,619

Timestamp

10/25/2013, 1:10:22 AM

Confirmations

6,580,176

Merkle Root

197964dcc80bdf55087b8c1af37ba83cd0f0433259b6a2e2aa3473ce09f8805d
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.

9.928 × 10⁹²(93-digit number)
99283141502612735261…26074040229216999751
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
9.928 × 10⁹²(93-digit number)
99283141502612735261…26074040229216999751
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.985 × 10⁹³(94-digit number)
19856628300522547052…52148080458433999501
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
3.971 × 10⁹³(94-digit number)
39713256601045094104…04296160916867999001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
7.942 × 10⁹³(94-digit number)
79426513202090188209…08592321833735998001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.588 × 10⁹⁴(95-digit number)
15885302640418037641…17184643667471996001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
3.177 × 10⁹⁴(95-digit number)
31770605280836075283…34369287334943992001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
6.354 × 10⁹⁴(95-digit number)
63541210561672150567…68738574669887984001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.270 × 10⁹⁵(96-digit number)
12708242112334430113…37477149339775968001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.541 × 10⁹⁵(96-digit number)
25416484224668860226…74954298679551936001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
5.083 × 10⁹⁵(96-digit number)
50832968449337720453…49908597359103872001
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:57,695,007 XPM·at block #6,806,364 · updates every 60s
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