Block #330,927

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/27/2013, 12:30:28 AM · Difficulty 10.1686 · 6,468,345 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
43b5210225c9ddf53a2ab051d3a4ed4e86358f5ed410021a836f4d3135b34217

Height

#330,927

Difficulty

10.168595

Transactions

15

Size

4.84 KB

Version

2

Bits

0a2b2908

Nonce

487,521

Timestamp

12/27/2013, 12:30:28 AM

Confirmations

6,468,345

Merkle Root

6a9330db723f01f9c56bcec9cf09c140df1159bfccac0bfeeab46dae94844ba7
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.

2.196 × 10⁹²(93-digit number)
21960353820103693599…31290362272390958201
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
2.196 × 10⁹²(93-digit number)
21960353820103693599…31290362272390958201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
4.392 × 10⁹²(93-digit number)
43920707640207387198…62580724544781916401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
8.784 × 10⁹²(93-digit number)
87841415280414774397…25161449089563832801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.756 × 10⁹³(94-digit number)
17568283056082954879…50322898179127665601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
3.513 × 10⁹³(94-digit number)
35136566112165909758…00645796358255331201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
7.027 × 10⁹³(94-digit number)
70273132224331819517…01291592716510662401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.405 × 10⁹⁴(95-digit number)
14054626444866363903…02583185433021324801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.810 × 10⁹⁴(95-digit number)
28109252889732727807…05166370866042649601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
5.621 × 10⁹⁴(95-digit number)
56218505779465455614…10332741732085299201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.124 × 10⁹⁵(96-digit number)
11243701155893091122…20665483464170598401
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:57,638,216 XPM·at block #6,799,271 · updates every 60s
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