Block #329,442

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/25/2013, 11:25:27 PM · Difficulty 10.1715 · 6,463,140 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
a446d483d83c6da1cc88c2aedf7889ab096809dfeb42d00e0eebc3ca511d8806

Height

#329,442

Difficulty

10.171511

Transactions

18

Size

4.99 KB

Version

2

Bits

0a2be81e

Nonce

11,551

Timestamp

12/25/2013, 11:25:27 PM

Confirmations

6,463,140

Merkle Root

a9fa249d3dcdb56d6acc23272c5a47ba9d867f22003e488dd78e12f9f6e1cb56
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.

5.909 × 10⁹¹(92-digit number)
59096791359247282718…24269298609678032511
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
5.909 × 10⁹¹(92-digit number)
59096791359247282718…24269298609678032511
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.181 × 10⁹²(93-digit number)
11819358271849456543…48538597219356065021
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.363 × 10⁹²(93-digit number)
23638716543698913087…97077194438712130041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
4.727 × 10⁹²(93-digit number)
47277433087397826174…94154388877424260081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
9.455 × 10⁹²(93-digit number)
94554866174795652349…88308777754848520161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.891 × 10⁹³(94-digit number)
18910973234959130469…76617555509697040321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
3.782 × 10⁹³(94-digit number)
37821946469918260939…53235111019394080641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
7.564 × 10⁹³(94-digit number)
75643892939836521879…06470222038788161281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.512 × 10⁹⁴(95-digit number)
15128778587967304375…12940444077576322561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
3.025 × 10⁹⁴(95-digit number)
30257557175934608751…25880888155152645121
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:57,584,625 XPM·at block #6,792,581 · 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.