Block #2,794,213

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 8/14/2018, 10:24:54 PM · Difficulty 11.6780 · 4,049,674 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
828d442a9c297b3e13593fa3479222b6bbb3a619505cc3717b1f89f60daf2a37

Height

#2,794,213

Difficulty

11.677952

Transactions

26

Size

6.48 KB

Version

2

Bits

0bad8e46

Nonce

732,544,617

Timestamp

8/14/2018, 10:24:54 PM

Confirmations

4,049,674

Merkle Root

10fb616db41231d66ba4b049cbf296f99d8edc602d4b4f8f52bfe3a4e88613b9
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.

2.403 × 10⁹⁶(97-digit number)
24031139854729317060…01997822237734475841
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
2.403 × 10⁹⁶(97-digit number)
24031139854729317060…01997822237734475841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
4.806 × 10⁹⁶(97-digit number)
48062279709458634121…03995644475468951681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
9.612 × 10⁹⁶(97-digit number)
96124559418917268243…07991288950937903361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.922 × 10⁹⁷(98-digit number)
19224911883783453648…15982577901875806721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
3.844 × 10⁹⁷(98-digit number)
38449823767566907297…31965155803751613441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
7.689 × 10⁹⁷(98-digit number)
76899647535133814595…63930311607503226881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.537 × 10⁹⁸(99-digit number)
15379929507026762919…27860623215006453761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
3.075 × 10⁹⁸(99-digit number)
30759859014053525838…55721246430012907521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
6.151 × 10⁹⁸(99-digit number)
61519718028107051676…11442492860025815041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.230 × 10⁹⁹(100-digit number)
12303943605621410335…22884985720051630081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
2.460 × 10⁹⁹(100-digit number)
24607887211242820670…45769971440103260161
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:57,995,465 XPM·at block #6,843,886 · updates every 60s
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