Block #368,224

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 1/20/2014, 2:32:35 PM · Difficulty 10.4395 · 6,446,242 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
187136e9a93dcb0825f3ec95611aa14b98fc68f118ef013667443f0e85201177

Height

#368,224

Difficulty

10.439539

Transactions

5

Size

1.22 KB

Version

2

Bits

0a7085a3

Nonce

24,534

Timestamp

1/20/2014, 2:32:35 PM

Confirmations

6,446,242

Merkle Root

b4b521a6c80c89a6205b0e842b55759437bbd93dd932183789c69443f0b44944
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.

1.209 × 10¹⁰⁰(101-digit number)
12096464748724829943…07340021519477776451
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
1.209 × 10¹⁰⁰(101-digit number)
12096464748724829943…07340021519477776451
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.419 × 10¹⁰⁰(101-digit number)
24192929497449659886…14680043038955552901
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
4.838 × 10¹⁰⁰(101-digit number)
48385858994899319773…29360086077911105801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
9.677 × 10¹⁰⁰(101-digit number)
96771717989798639546…58720172155822211601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.935 × 10¹⁰¹(102-digit number)
19354343597959727909…17440344311644423201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
3.870 × 10¹⁰¹(102-digit number)
38708687195919455818…34880688623288846401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
7.741 × 10¹⁰¹(102-digit number)
77417374391838911637…69761377246577692801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.548 × 10¹⁰²(103-digit number)
15483474878367782327…39522754493155385601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
3.096 × 10¹⁰²(103-digit number)
30966949756735564654…79045508986310771201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
6.193 × 10¹⁰²(103-digit number)
61933899513471129309…58091017972621542401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
1.238 × 10¹⁰³(104-digit number)
12386779902694225861…16182035945243084801
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 11 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
RareChain length 11

Approximately 1 in 1,000 blocks. Noteworthy discoveries.

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:57,759,801 XPM·at block #6,814,465 · updates every 60s
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