Block #3,186,341

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 5/17/2019, 6:49:57 PM · Difficulty 11.2421 · 3,654,469 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
6797b2daa6fe5d4a484b5703b19753adad7cd021a1e828aa3bab7fc31ab1615b

Height

#3,186,341

Difficulty

11.242148

Transactions

6

Size

2.16 KB

Version

2

Bits

0b3dfd66

Nonce

608,000,550

Timestamp

5/17/2019, 6:49:57 PM

Confirmations

3,654,469

Merkle Root

c5616688d10c9fcd34e66c56b6598b4be528fb2c45b974ccd84e32d9b8fae8c9
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.

2.600 × 10⁹⁵(96-digit number)
26001343337180215346…66428878777766633121
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
2.600 × 10⁹⁵(96-digit number)
26001343337180215346…66428878777766633121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
5.200 × 10⁹⁵(96-digit number)
52002686674360430693…32857757555533266241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.040 × 10⁹⁶(97-digit number)
10400537334872086138…65715515111066532481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.080 × 10⁹⁶(97-digit number)
20801074669744172277…31431030222133064961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
4.160 × 10⁹⁶(97-digit number)
41602149339488344554…62862060444266129921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
8.320 × 10⁹⁶(97-digit number)
83204298678976689109…25724120888532259841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.664 × 10⁹⁷(98-digit number)
16640859735795337821…51448241777064519681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
3.328 × 10⁹⁷(98-digit number)
33281719471590675643…02896483554129039361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
6.656 × 10⁹⁷(98-digit number)
66563438943181351287…05792967108258078721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.331 × 10⁹⁸(99-digit number)
13312687788636270257…11585934216516157441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
2.662 × 10⁹⁸(99-digit number)
26625375577272540515…23171868433032314881
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:57,970,830 XPM·at block #6,840,809 · updates every 60s
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