Block #3,051,937

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 2/14/2019, 2:19:24 AM · Difficulty 11.0006 · 3,785,620 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
fa6cbebedb5539a557a8863a913b9cc97231eea5b29184753fddd804e0e9e230

Height

#3,051,937

Difficulty

11.000626

Transactions

2

Size

3.60 KB

Version

2

Bits

0b002905

Nonce

14,301,117

Timestamp

2/14/2019, 2:19:24 AM

Confirmations

3,785,620

Merkle Root

0c613f304158b03663ef4b0be164237f45e95ef1c2e8b0f2eb340df523fafdbb
Transactions (2)
1 in → 1 out8.2900 XPM109 B
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.

3.546 × 10⁹⁶(97-digit number)
35466711678080397975…29784803801165931841
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
3.546 × 10⁹⁶(97-digit number)
35466711678080397975…29784803801165931841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
7.093 × 10⁹⁶(97-digit number)
70933423356160795950…59569607602331863681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.418 × 10⁹⁷(98-digit number)
14186684671232159190…19139215204663727361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.837 × 10⁹⁷(98-digit number)
28373369342464318380…38278430409327454721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
5.674 × 10⁹⁷(98-digit number)
56746738684928636760…76556860818654909441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.134 × 10⁹⁸(99-digit number)
11349347736985727352…53113721637309818881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.269 × 10⁹⁸(99-digit number)
22698695473971454704…06227443274619637761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
4.539 × 10⁹⁸(99-digit number)
45397390947942909408…12454886549239275521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
9.079 × 10⁹⁸(99-digit number)
90794781895885818816…24909773098478551041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.815 × 10⁹⁹(100-digit number)
18158956379177163763…49819546196957102081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
3.631 × 10⁹⁹(100-digit number)
36317912758354327526…99639092393914204161
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:57,944,785 XPM·at block #6,837,556 · updates every 60s
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