Block #2,934,735

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 11/22/2018, 6:50:18 PM · Difficulty 11.3932 · 3,905,472 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
893f3acf4fa7fc49a49593423a1a53ed1343dd5aae2a35007c544a3a40aee6f4

Height

#2,934,735

Difficulty

11.393226

Transactions

25

Size

7.33 KB

Version

2

Bits

0b64aa6e

Nonce

119,316,835

Timestamp

11/22/2018, 6:50:18 PM

Confirmations

3,905,472

Merkle Root

d89542cbed0f7b6680aa76b116b3d49d83ea96fd4e978ad3f1d2f08b1d82fa68
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.

6.731 × 10⁹⁵(96-digit number)
67311778806828713981…05708010234549107841
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
6.731 × 10⁹⁵(96-digit number)
67311778806828713981…05708010234549107841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.346 × 10⁹⁶(97-digit number)
13462355761365742796…11416020469098215681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.692 × 10⁹⁶(97-digit number)
26924711522731485592…22832040938196431361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
5.384 × 10⁹⁶(97-digit number)
53849423045462971185…45664081876392862721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.076 × 10⁹⁷(98-digit number)
10769884609092594237…91328163752785725441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.153 × 10⁹⁷(98-digit number)
21539769218185188474…82656327505571450881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
4.307 × 10⁹⁷(98-digit number)
43079538436370376948…65312655011142901761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
8.615 × 10⁹⁷(98-digit number)
86159076872740753896…30625310022285803521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.723 × 10⁹⁸(99-digit number)
17231815374548150779…61250620044571607041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
3.446 × 10⁹⁸(99-digit number)
34463630749096301558…22501240089143214081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
6.892 × 10⁹⁸(99-digit number)
68927261498192603117…45002480178286428161
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:57,965,973 XPM·at block #6,840,206 · updates every 60s
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