Block #334,960

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/29/2013, 8:47:15 PM · Difficulty 10.1599 · 6,474,555 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
1851b187700ba8ef364e4e0ad747650c00f65b239140f0e8e9ffc828af0b1729

Height

#334,960

Difficulty

10.159869

Transactions

6

Size

1.59 KB

Version

2

Bits

0a28ed25

Nonce

44,988

Timestamp

12/29/2013, 8:47:15 PM

Confirmations

6,474,555

Merkle Root

ec40068c3b9fb356c35f118b9759002c5e655403bef09194c1464b300a32e2bc
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.

6.478 × 10⁹³(94-digit number)
64785939988396259288…08822729749326620161
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
6.478 × 10⁹³(94-digit number)
64785939988396259288…08822729749326620161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.295 × 10⁹⁴(95-digit number)
12957187997679251857…17645459498653240321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.591 × 10⁹⁴(95-digit number)
25914375995358503715…35290918997306480641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
5.182 × 10⁹⁴(95-digit number)
51828751990717007430…70581837994612961281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.036 × 10⁹⁵(96-digit number)
10365750398143401486…41163675989225922561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.073 × 10⁹⁵(96-digit number)
20731500796286802972…82327351978451845121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
4.146 × 10⁹⁵(96-digit number)
41463001592573605944…64654703956903690241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
8.292 × 10⁹⁵(96-digit number)
82926003185147211888…29309407913807380481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.658 × 10⁹⁶(97-digit number)
16585200637029442377…58618815827614760961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
3.317 × 10⁹⁶(97-digit number)
33170401274058884755…17237631655229521921
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:57,720,196 XPM·at block #6,809,514 · updates every 60s
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