Block #330,899

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/27/2013, 12:02:32 AM · Difficulty 10.1685 · 6,465,207 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
5fdb390656d4c0fc7df18c49746a9778eeb6def229ca838f48bd0c0f84c947eb

Height

#330,899

Difficulty

10.168506

Transactions

12

Size

3.61 KB

Version

2

Bits

0a2b2333

Nonce

89,473

Timestamp

12/27/2013, 12:02:32 AM

Confirmations

6,465,207

Merkle Root

3145197de9eb6fe6d5e69ddef1ca0c2c1c312de55c57bc62a2f8230a293963bb
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.

4.816 × 10⁹⁶(97-digit number)
48166327248295224411…54570696404263761921
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
4.816 × 10⁹⁶(97-digit number)
48166327248295224411…54570696404263761921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
9.633 × 10⁹⁶(97-digit number)
96332654496590448823…09141392808527523841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.926 × 10⁹⁷(98-digit number)
19266530899318089764…18282785617055047681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
3.853 × 10⁹⁷(98-digit number)
38533061798636179529…36565571234110095361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
7.706 × 10⁹⁷(98-digit number)
77066123597272359058…73131142468220190721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.541 × 10⁹⁸(99-digit number)
15413224719454471811…46262284936440381441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
3.082 × 10⁹⁸(99-digit number)
30826449438908943623…92524569872880762881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
6.165 × 10⁹⁸(99-digit number)
61652898877817887246…85049139745761525761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.233 × 10⁹⁹(100-digit number)
12330579775563577449…70098279491523051521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.466 × 10⁹⁹(100-digit number)
24661159551127154898…40196558983046103041
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:57,612,842 XPM·at block #6,796,105 · updates every 60s
xpmprime.info is a work in progress. If you enjoy using this service you can support this project with a Primecoin donation.