Block #334,747

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/29/2013, 5:13:06 PM · Difficulty 10.1599 · 6,473,260 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
04545b786f84aea2da612bd85f3c5145d3ccf69a57c9fb7b7b1d6bbcfe67685e

Height

#334,747

Difficulty

10.159891

Transactions

13

Size

7.14 KB

Version

2

Bits

0a28ee9b

Nonce

72,486

Timestamp

12/29/2013, 5:13:06 PM

Confirmations

6,473,260

Merkle Root

15940d86b9c37430f8f6b65737b924ab829432640acd6f5044e707393f182095
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.

2.671 × 10⁹³(94-digit number)
26712122669196510398…43944987374074784301
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
2.671 × 10⁹³(94-digit number)
26712122669196510398…43944987374074784301
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
5.342 × 10⁹³(94-digit number)
53424245338393020797…87889974748149568601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.068 × 10⁹⁴(95-digit number)
10684849067678604159…75779949496299137201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.136 × 10⁹⁴(95-digit number)
21369698135357208318…51559898992598274401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
4.273 × 10⁹⁴(95-digit number)
42739396270714416637…03119797985196548801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
8.547 × 10⁹⁴(95-digit number)
85478792541428833275…06239595970393097601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.709 × 10⁹⁵(96-digit number)
17095758508285766655…12479191940786195201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
3.419 × 10⁹⁵(96-digit number)
34191517016571533310…24958383881572390401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
6.838 × 10⁹⁵(96-digit number)
68383034033143066620…49916767763144780801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.367 × 10⁹⁶(97-digit number)
13676606806628613324…99833535526289561601
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:57,708,097 XPM·at block #6,808,006 · updates every 60s
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