Block #336,734

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/31/2013, 4:14:12 AM · Difficulty 10.1418 · 6,459,379 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
d891ca8c77e96f4625a785a71ff03657747694f12e85ed96751f6d3978ad9c96

Height

#336,734

Difficulty

10.141783

Transactions

12

Size

2.63 KB

Version

2

Bits

0a244bde

Nonce

153,095

Timestamp

12/31/2013, 4:14:12 AM

Confirmations

6,459,379

Merkle Root

f9a9a09885ac9e4251355d0cce38ca6ab6e7b81789404bee7a6207dbeb4f2bb5
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.

1.224 × 10¹⁰¹(102-digit number)
12242995554035237082…47139365605755362241
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
1.224 × 10¹⁰¹(102-digit number)
12242995554035237082…47139365605755362241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.448 × 10¹⁰¹(102-digit number)
24485991108070474164…94278731211510724481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
4.897 × 10¹⁰¹(102-digit number)
48971982216140948329…88557462423021448961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
9.794 × 10¹⁰¹(102-digit number)
97943964432281896658…77114924846042897921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.958 × 10¹⁰²(103-digit number)
19588792886456379331…54229849692085795841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
3.917 × 10¹⁰²(103-digit number)
39177585772912758663…08459699384171591681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
7.835 × 10¹⁰²(103-digit number)
78355171545825517326…16919398768343183361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.567 × 10¹⁰³(104-digit number)
15671034309165103465…33838797536686366721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
3.134 × 10¹⁰³(104-digit number)
31342068618330206930…67677595073372733441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
6.268 × 10¹⁰³(104-digit number)
62684137236660413861…35355190146745466881
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:57,612,899 XPM·at block #6,796,112 · updates every 60s
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