Block #2,584,196

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 3/25/2018, 4:53:24 AM · Difficulty 11.2006 · 4,258,819 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
1bb9d831be03c0c8937b68797c449e19d27dfe5be138e8343c01d3c1a0f615af

Height

#2,584,196

Difficulty

11.200638

Transactions

6

Size

2.11 KB

Version

2

Bits

0b335d03

Nonce

1,290,948,130

Timestamp

3/25/2018, 4:53:24 AM

Confirmations

4,258,819

Merkle Root

0d347db2362c86e9c03ee1fbdf2ce3f13781721c8bd14e4b5e8828df4846841c
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.

3.500 × 10⁹⁶(97-digit number)
35004895411015649454…52112789228955024001
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
3.500 × 10⁹⁶(97-digit number)
35004895411015649454…52112789228955024001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
7.000 × 10⁹⁶(97-digit number)
70009790822031298909…04225578457910048001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.400 × 10⁹⁷(98-digit number)
14001958164406259781…08451156915820096001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.800 × 10⁹⁷(98-digit number)
28003916328812519563…16902313831640192001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
5.600 × 10⁹⁷(98-digit number)
56007832657625039127…33804627663280384001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.120 × 10⁹⁸(99-digit number)
11201566531525007825…67609255326560768001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.240 × 10⁹⁸(99-digit number)
22403133063050015651…35218510653121536001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
4.480 × 10⁹⁸(99-digit number)
44806266126100031302…70437021306243072001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
8.961 × 10⁹⁸(99-digit number)
89612532252200062604…40874042612486144001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.792 × 10⁹⁹(100-digit number)
17922506450440012520…81748085224972288001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
3.584 × 10⁹⁹(100-digit number)
35845012900880025041…63496170449944576001
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:57,988,475 XPM·at block #6,843,014 · updates every 60s
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