Block #3,006,897

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 1/12/2019, 8:52:24 PM · Difficulty 11.2026 · 3,831,192 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
2119ee4fe6a891313c8d35cec2ecd099cb07d0ed7454907794139d65219d4d67

Height

#3,006,897

Difficulty

11.202562

Transactions

23

Size

5.54 KB

Version

2

Bits

0b33db1e

Nonce

242,825,233

Timestamp

1/12/2019, 8:52:24 PM

Confirmations

3,831,192

Merkle Root

2531e3a66df5d46a80b6fe57571bd426aecaf34bc9fde77a722501d74109837d
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.

4.740 × 10⁹⁵(96-digit number)
47405787134158857684…07258274192938902921
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
4.740 × 10⁹⁵(96-digit number)
47405787134158857684…07258274192938902921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
9.481 × 10⁹⁵(96-digit number)
94811574268317715368…14516548385877805841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.896 × 10⁹⁶(97-digit number)
18962314853663543073…29033096771755611681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
3.792 × 10⁹⁶(97-digit number)
37924629707327086147…58066193543511223361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
7.584 × 10⁹⁶(97-digit number)
75849259414654172294…16132387087022446721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.516 × 10⁹⁷(98-digit number)
15169851882930834458…32264774174044893441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
3.033 × 10⁹⁷(98-digit number)
30339703765861668917…64529548348089786881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
6.067 × 10⁹⁷(98-digit number)
60679407531723337835…29059096696179573761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.213 × 10⁹⁸(99-digit number)
12135881506344667567…58118193392359147521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.427 × 10⁹⁸(99-digit number)
24271763012689335134…16236386784718295041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
4.854 × 10⁹⁸(99-digit number)
48543526025378670268…32472773569436590081
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:57,949,062 XPM·at block #6,838,088 · updates every 60s
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