Block #2,800,892

1CCLength 11★★★☆☆

Cunningham Chain of the First Kind · Discovered 8/19/2018, 3:29:49 PM · Difficulty 11.6713 · 4,041,318 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
db9f5c6ffc33c072a25ffe5c49ac9487adf6d985cac94de4d5f253e4d8335cd5

Height

#2,800,892

Difficulty

11.671283

Transactions

24

Size

7.17 KB

Version

2

Bits

0babd93c

Nonce

1,025,943,330

Timestamp

8/19/2018, 3:29:49 PM

Confirmations

4,041,318

Merkle Root

d428c8ace1ab3d78a1e3dbeb21fb4fa03d49948e2af803c6b5dff76872b4dc63
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.

6.227 × 10⁹⁶(97-digit number)
62271686526635848715…85372212440849233919
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
6.227 × 10⁹⁶(97-digit number)
62271686526635848715…85372212440849233919
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
1.245 × 10⁹⁷(98-digit number)
12454337305327169743…70744424881698467839
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
2.490 × 10⁹⁷(98-digit number)
24908674610654339486…41488849763396935679
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
4.981 × 10⁹⁷(98-digit number)
49817349221308678972…82977699526793871359
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
9.963 × 10⁹⁷(98-digit number)
99634698442617357944…65955399053587742719
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
1.992 × 10⁹⁸(99-digit number)
19926939688523471588…31910798107175485439
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
3.985 × 10⁹⁸(99-digit number)
39853879377046943177…63821596214350970879
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
7.970 × 10⁹⁸(99-digit number)
79707758754093886355…27643192428701941759
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
1.594 × 10⁹⁹(100-digit number)
15941551750818777271…55286384857403883519
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
3.188 × 10⁹⁹(100-digit number)
31883103501637554542…10572769714807767039
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
11
2^10 × origin − 1
6.376 × 10⁹⁹(100-digit number)
63766207003275109084…21145539429615534079
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 First 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 1CC formula:

1CC: p₁ (first prime), p₂ = 2p₁ + 1, p₃ = 2p₂ + 1, …
Circulating Supply:57,982,076 XPM·at block #6,842,209 · updates every 60s
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