Block #424,848

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 3/1/2014, 11:58:38 AM · Difficulty 10.3636 · 6,385,792 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
dfd6bdd1ca4b1467ee39c5d80b2891f8d04f5bf807470c33fdf51095dd747eb0

Height

#424,848

Difficulty

10.363567

Transactions

2

Size

1.16 KB

Version

2

Bits

0a5d12bb

Nonce

214,251

Timestamp

3/1/2014, 11:58:38 AM

Confirmations

6,385,792

Merkle Root

985e0eee4cda8fbca95c8742468829c8a9d3cbaf2ea661746c8117a7e68e88b1
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.

4.530 × 10⁹³(94-digit number)
45303256191786157594…43174125006413131241
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
4.530 × 10⁹³(94-digit number)
45303256191786157594…43174125006413131241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
9.060 × 10⁹³(94-digit number)
90606512383572315189…86348250012826262481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.812 × 10⁹⁴(95-digit number)
18121302476714463037…72696500025652524961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
3.624 × 10⁹⁴(95-digit number)
36242604953428926075…45393000051305049921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
7.248 × 10⁹⁴(95-digit number)
72485209906857852151…90786000102610099841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.449 × 10⁹⁵(96-digit number)
14497041981371570430…81572000205220199681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.899 × 10⁹⁵(96-digit number)
28994083962743140860…63144000410440399361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
5.798 × 10⁹⁵(96-digit number)
57988167925486281721…26288000820880798721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.159 × 10⁹⁶(97-digit number)
11597633585097256344…52576001641761597441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.319 × 10⁹⁶(97-digit number)
23195267170194512688…05152003283523194881
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:57,729,208 XPM·at block #6,810,639 · updates every 60s
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