Block #504,966

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 4/22/2014, 3:26:28 AM · Difficulty 10.8098 · 6,299,846 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
11f00ef0adc3df746f91e20eb9ba628e2946f2526ab8213d9f132df1ebd615c2

Height

#504,966

Difficulty

10.809813

Transactions

3

Size

1.54 KB

Version

2

Bits

0acf4fe6

Nonce

152,192

Timestamp

4/22/2014, 3:26:28 AM

Confirmations

6,299,846

Merkle Root

3f11a78516c70e0ee6a5943dad6dca57ddd8689ded26443fe3e13cd6713f7122
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.

1.674 × 10⁹⁸(99-digit number)
16749443561911798284…55459808420054337001
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
1.674 × 10⁹⁸(99-digit number)
16749443561911798284…55459808420054337001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
3.349 × 10⁹⁸(99-digit number)
33498887123823596569…10919616840108674001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
6.699 × 10⁹⁸(99-digit number)
66997774247647193139…21839233680217348001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.339 × 10⁹⁹(100-digit number)
13399554849529438627…43678467360434696001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.679 × 10⁹⁹(100-digit number)
26799109699058877255…87356934720869392001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
5.359 × 10⁹⁹(100-digit number)
53598219398117754511…74713869441738784001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.071 × 10¹⁰⁰(101-digit number)
10719643879623550902…49427738883477568001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.143 × 10¹⁰⁰(101-digit number)
21439287759247101804…98855477766955136001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
4.287 × 10¹⁰⁰(101-digit number)
42878575518494203609…97710955533910272001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
8.575 × 10¹⁰⁰(101-digit number)
85757151036988407218…95421911067820544001
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:57,682,565 XPM·at block #6,804,811 · updates every 60s
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