Block #3,111,329

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 3/26/2019, 4:44:50 PM · Difficulty 11.2381 · 3,713,398 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
f5db5de497450f575a376d0aeab316d2b5d797bf86e35ab9506ea2c3de3676d1

Height

#3,111,329

Difficulty

11.238148

Transactions

16

Size

4.49 KB

Version

2

Bits

0b3cf743

Nonce

451,837,801

Timestamp

3/26/2019, 4:44:50 PM

Confirmations

3,713,398

Merkle Root

5dd1300c14ac44c8122b77f0cec5fd74398199ba0faba2e059cc1807b6847713
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.

8.380 × 10⁹⁴(95-digit number)
83801992791004610236…32226951365185131521
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
8.380 × 10⁹⁴(95-digit number)
83801992791004610236…32226951365185131521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.676 × 10⁹⁵(96-digit number)
16760398558200922047…64453902730370263041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
3.352 × 10⁹⁵(96-digit number)
33520797116401844094…28907805460740526081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
6.704 × 10⁹⁵(96-digit number)
67041594232803688189…57815610921481052161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.340 × 10⁹⁶(97-digit number)
13408318846560737637…15631221842962104321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.681 × 10⁹⁶(97-digit number)
26816637693121475275…31262443685924208641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
5.363 × 10⁹⁶(97-digit number)
53633275386242950551…62524887371848417281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.072 × 10⁹⁷(98-digit number)
10726655077248590110…25049774743696834561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.145 × 10⁹⁷(98-digit number)
21453310154497180220…50099549487393669121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
4.290 × 10⁹⁷(98-digit number)
42906620308994360441…00199098974787338241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
8.581 × 10⁹⁷(98-digit number)
85813240617988720882…00398197949574676481
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:57,841,883 XPM·at block #6,824,726 · updates every 60s
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