Block #324,416

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/22/2013, 8:00:38 AM · Difficulty 10.2062 · 6,472,398 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
c815a2500b55c1a04c75b7f29be112ebd46c5e6212802418b16ee2629a259d0c

Height

#324,416

Difficulty

10.206165

Transactions

17

Size

4.53 KB

Version

2

Bits

0a34c742

Nonce

156,344

Timestamp

12/22/2013, 8:00:38 AM

Confirmations

6,472,398

Merkle Root

a35869053b6e32c2a0cf6f36b84b1b696d55fb16d76398004503c5fc77f09123
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.

1.054 × 10⁹⁶(97-digit number)
10540630180044755427…16069965789978588161
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
1.054 × 10⁹⁶(97-digit number)
10540630180044755427…16069965789978588161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.108 × 10⁹⁶(97-digit number)
21081260360089510855…32139931579957176321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
4.216 × 10⁹⁶(97-digit number)
42162520720179021710…64279863159914352641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
8.432 × 10⁹⁶(97-digit number)
84325041440358043421…28559726319828705281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.686 × 10⁹⁷(98-digit number)
16865008288071608684…57119452639657410561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
3.373 × 10⁹⁷(98-digit number)
33730016576143217368…14238905279314821121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
6.746 × 10⁹⁷(98-digit number)
67460033152286434737…28477810558629642241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.349 × 10⁹⁸(99-digit number)
13492006630457286947…56955621117259284481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.698 × 10⁹⁸(99-digit number)
26984013260914573894…13911242234518568961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
5.396 × 10⁹⁸(99-digit number)
53968026521829147789…27822484469037137921
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:57,618,520 XPM·at block #6,796,813 · updates every 60s
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