Block #324,046

2CCLength 12★★★★☆

Cunningham Chain of the Second Kind · Discovered 12/22/2013, 1:39:49 AM · Difficulty 10.2072 · 6,482,624 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
18efebf456e0234111c4d2cbefce9d4bedf34d0064c40abc387128d6d13866c2

Height

#324,046

Difficulty

10.207158

Transactions

2

Size

1.10 KB

Version

2

Bits

0a35084c

Nonce

164,176

Timestamp

12/22/2013, 1:39:49 AM

Confirmations

6,482,624

Merkle Root

f8324f51e0078d0d9f045571259c4d4458c17885174ea291b9506258620aec30
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.

6.759 × 10⁹²(93-digit number)
67595267911328234717…29264370088162336001
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
6.759 × 10⁹²(93-digit number)
67595267911328234717…29264370088162336001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.351 × 10⁹³(94-digit number)
13519053582265646943…58528740176324672001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.703 × 10⁹³(94-digit number)
27038107164531293887…17057480352649344001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
5.407 × 10⁹³(94-digit number)
54076214329062587774…34114960705298688001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.081 × 10⁹⁴(95-digit number)
10815242865812517554…68229921410597376001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.163 × 10⁹⁴(95-digit number)
21630485731625035109…36459842821194752001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
4.326 × 10⁹⁴(95-digit number)
43260971463250070219…72919685642389504001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
8.652 × 10⁹⁴(95-digit number)
86521942926500140439…45839371284779008001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.730 × 10⁹⁵(96-digit number)
17304388585300028087…91678742569558016001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
3.460 × 10⁹⁵(96-digit number)
34608777170600056175…83357485139116032001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
6.921 × 10⁹⁵(96-digit number)
69217554341200112351…66714970278232064001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
12
2^11 × origin + 1
1.384 × 10⁹⁶(97-digit number)
13843510868240022470…33429940556464128001
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 12 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
ExceptionalChain length 12

Around 1 in 10,000 blocks. A significant mathematical achievement.

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:57,697,459 XPM·at block #6,806,669 · updates every 60s
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