Block #282,414

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 11/29/2013, 9:20:32 AM · Difficulty 9.9791 · 6,521,357 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
7dca1e3c4454c8c2982bbf1f1cf8889206a5f43edf246bde87fe443aa560b556

Height

#282,414

Difficulty

9.979058

Transactions

6

Size

1.92 KB

Version

2

Bits

09faa385

Nonce

5,067

Timestamp

11/29/2013, 9:20:32 AM

Confirmations

6,521,357

Merkle Root

cffa3d063b84d22ab2e9359572e30a7017aa9cde127e3018d80bb8daefae47f1
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.

7.189 × 10⁹⁹(100-digit number)
71898966968949660645…79260892358441584481
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
7.189 × 10⁹⁹(100-digit number)
71898966968949660645…79260892358441584481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.437 × 10¹⁰⁰(101-digit number)
14379793393789932129…58521784716883168961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.875 × 10¹⁰⁰(101-digit number)
28759586787579864258…17043569433766337921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
5.751 × 10¹⁰⁰(101-digit number)
57519173575159728516…34087138867532675841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.150 × 10¹⁰¹(102-digit number)
11503834715031945703…68174277735065351681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.300 × 10¹⁰¹(102-digit number)
23007669430063891406…36348555470130703361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
4.601 × 10¹⁰¹(102-digit number)
46015338860127782813…72697110940261406721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
9.203 × 10¹⁰¹(102-digit number)
92030677720255565626…45394221880522813441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.840 × 10¹⁰²(103-digit number)
18406135544051113125…90788443761045626881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
3.681 × 10¹⁰²(103-digit number)
36812271088102226250…81576887522091253761
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:57,674,206 XPM·at block #6,803,770 · updates every 60s
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