Block #3,049,697

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 2/12/2019, 11:25:27 AM · Difficulty 11.0019 · 3,792,499 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
677a0a59399aa1e81062c7996e8949b3a03263fb3e66ded7ba9f881ff1b7e67a

Height

#3,049,697

Difficulty

11.001918

Transactions

2

Size

574 B

Version

2

Bits

0b007db1

Nonce

1,978,420,099

Timestamp

2/12/2019, 11:25:27 AM

Confirmations

3,792,499

Merkle Root

f5c7a2ca31bfbfbc389722348547f544e85b6ec9198eee4847cffb115f09481c
Transactions (2)
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.

1.782 × 10⁹⁸(99-digit number)
17823977256949363702…99010042824761978881
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
1.782 × 10⁹⁸(99-digit number)
17823977256949363702…99010042824761978881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
3.564 × 10⁹⁸(99-digit number)
35647954513898727405…98020085649523957761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
7.129 × 10⁹⁸(99-digit number)
71295909027797454810…96040171299047915521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.425 × 10⁹⁹(100-digit number)
14259181805559490962…92080342598095831041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.851 × 10⁹⁹(100-digit number)
28518363611118981924…84160685196191662081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
5.703 × 10⁹⁹(100-digit number)
57036727222237963848…68321370392383324161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.140 × 10¹⁰⁰(101-digit number)
11407345444447592769…36642740784766648321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.281 × 10¹⁰⁰(101-digit number)
22814690888895185539…73285481569533296641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
4.562 × 10¹⁰⁰(101-digit number)
45629381777790371078…46570963139066593281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
9.125 × 10¹⁰⁰(101-digit number)
91258763555580742156…93141926278133186561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
1.825 × 10¹⁰¹(102-digit number)
18251752711116148431…86283852556266373121
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:57,981,962 XPM·at block #6,842,195 · updates every 60s
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