Block #326,885

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/24/2013, 3:45:17 AM · Difficulty 10.1811 · 6,464,598 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
2bef21178a7e7def204817f04923d6371ee25937101b1b178c274f760add5379

Height

#326,885

Difficulty

10.181137

Transactions

6

Size

2.14 KB

Version

2

Bits

0a2e5f03

Nonce

37,554

Timestamp

12/24/2013, 3:45:17 AM

Confirmations

6,464,598

Merkle Root

cd2088d01fe03617f85d382820fa3b6a673b50ef92da318f037abe5d807d5302
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.

9.450 × 10⁹⁵(96-digit number)
94507363540358129398…41809005518845359201
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
9.450 × 10⁹⁵(96-digit number)
94507363540358129398…41809005518845359201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.890 × 10⁹⁶(97-digit number)
18901472708071625879…83618011037690718401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
3.780 × 10⁹⁶(97-digit number)
37802945416143251759…67236022075381436801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
7.560 × 10⁹⁶(97-digit number)
75605890832286503518…34472044150762873601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.512 × 10⁹⁷(98-digit number)
15121178166457300703…68944088301525747201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
3.024 × 10⁹⁷(98-digit number)
30242356332914601407…37888176603051494401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
6.048 × 10⁹⁷(98-digit number)
60484712665829202815…75776353206102988801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.209 × 10⁹⁸(99-digit number)
12096942533165840563…51552706412205977601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.419 × 10⁹⁸(99-digit number)
24193885066331681126…03105412824411955201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
4.838 × 10⁹⁸(99-digit number)
48387770132663362252…06210825648823910401
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:57,575,803 XPM·at block #6,791,482 · updates every 60s
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