Block #439,541

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 3/11/2014, 6:30:35 PM · Difficulty 10.3594 · 6,363,812 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
2de51dcd430759b447cdd09e21596c613332ac2dd2dc4241663c81215b18b3d1

Height

#439,541

Difficulty

10.359416

Transactions

14

Size

3.36 KB

Version

2

Bits

0a5c02b0

Nonce

121,967

Timestamp

3/11/2014, 6:30:35 PM

Confirmations

6,363,812

Merkle Root

c24897816c9c242ab40f4ec8fadfa824829d37d92db8dd2faf07174fae2e62a5
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.

3.252 × 10⁹⁷(98-digit number)
32529235578716075924…55563877772172082701
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
3.252 × 10⁹⁷(98-digit number)
32529235578716075924…55563877772172082701
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
6.505 × 10⁹⁷(98-digit number)
65058471157432151848…11127755544344165401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.301 × 10⁹⁸(99-digit number)
13011694231486430369…22255511088688330801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.602 × 10⁹⁸(99-digit number)
26023388462972860739…44511022177376661601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
5.204 × 10⁹⁸(99-digit number)
52046776925945721478…89022044354753323201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.040 × 10⁹⁹(100-digit number)
10409355385189144295…78044088709506646401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.081 × 10⁹⁹(100-digit number)
20818710770378288591…56088177419013292801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
4.163 × 10⁹⁹(100-digit number)
41637421540756577182…12176354838026585601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
8.327 × 10⁹⁹(100-digit number)
83274843081513154365…24352709676053171201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.665 × 10¹⁰⁰(101-digit number)
16654968616302630873…48705419352106342401
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:57,670,859 XPM·at block #6,803,352 · updates every 60s
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