Block #326,314

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/23/2013, 5:08:14 PM · Difficulty 10.1918 · 6,484,617 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
ffc09cb18526ca75ed00da68052b2db83ae53d3416626581ed1188b503e159f7

Height

#326,314

Difficulty

10.191750

Transactions

23

Size

6.53 KB

Version

2

Bits

0a311689

Nonce

24,294

Timestamp

12/23/2013, 5:08:14 PM

Confirmations

6,484,617

Merkle Root

690d9370beac075e3bf74a25b1dd20a0bd5a1c9550de2c0b42d7bc2898403441
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.

2.682 × 10⁹⁷(98-digit number)
26823784930122015436…10234730968356523041
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
2.682 × 10⁹⁷(98-digit number)
26823784930122015436…10234730968356523041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
5.364 × 10⁹⁷(98-digit number)
53647569860244030872…20469461936713046081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.072 × 10⁹⁸(99-digit number)
10729513972048806174…40938923873426092161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.145 × 10⁹⁸(99-digit number)
21459027944097612348…81877847746852184321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
4.291 × 10⁹⁸(99-digit number)
42918055888195224697…63755695493704368641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
8.583 × 10⁹⁸(99-digit number)
85836111776390449395…27511390987408737281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.716 × 10⁹⁹(100-digit number)
17167222355278089879…55022781974817474561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
3.433 × 10⁹⁹(100-digit number)
34334444710556179758…10045563949634949121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
6.866 × 10⁹⁹(100-digit number)
68668889421112359516…20091127899269898241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.373 × 10¹⁰⁰(101-digit number)
13733777884222471903…40182255798539796481
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:57,731,551 XPM·at block #6,810,930 · updates every 60s
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