Block #327,724

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/24/2013, 6:31:09 PM · Difficulty 10.1738 · 6,471,196 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
d7eafd64edf7bff831dddaca4528f8fbcd3865463d63209bf7765f0b975d60a1

Height

#327,724

Difficulty

10.173757

Transactions

16

Size

84.79 KB

Version

2

Bits

0a2c7b52

Nonce

605,487

Timestamp

12/24/2013, 6:31:09 PM

Confirmations

6,471,196

Merkle Root

6384b652e54f33a9ad9bd66ec15ca88731b0998ff9ea67492e1e08130eaeb2bf
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.

1.196 × 10¹⁰⁰(101-digit number)
11964569181187132517…45876612222078048001
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
1.196 × 10¹⁰⁰(101-digit number)
11964569181187132517…45876612222078048001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.392 × 10¹⁰⁰(101-digit number)
23929138362374265034…91753224444156096001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
4.785 × 10¹⁰⁰(101-digit number)
47858276724748530069…83506448888312192001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
9.571 × 10¹⁰⁰(101-digit number)
95716553449497060139…67012897776624384001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.914 × 10¹⁰¹(102-digit number)
19143310689899412027…34025795553248768001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
3.828 × 10¹⁰¹(102-digit number)
38286621379798824055…68051591106497536001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
7.657 × 10¹⁰¹(102-digit number)
76573242759597648111…36103182212995072001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.531 × 10¹⁰²(103-digit number)
15314648551919529622…72206364425990144001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
3.062 × 10¹⁰²(103-digit number)
30629297103839059244…44412728851980288001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
6.125 × 10¹⁰²(103-digit number)
61258594207678118489…88825457703960576001
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:57,635,392 XPM·at block #6,798,919 · updates every 60s
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