Block #2,911,051

1CCLength 11★★★☆☆

Cunningham Chain of the First Kind · Discovered 11/5/2018, 10:24:53 AM · Difficulty 11.5309 · 3,922,222 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
b5cde112e71bc5ed169c9fa1c3f8f3bbf7dcc5839cf7cb8f3fe27654b0f5c8f8

Height

#2,911,051

Difficulty

11.530914

Transactions

7

Size

3.23 KB

Version

2

Bits

0b87e9f3

Nonce

577,106,873

Timestamp

11/5/2018, 10:24:53 AM

Confirmations

3,922,222

Merkle Root

28e80f3a4b77c2863ba58ed192c1ca9766b1a07620416530a078428fc56ba154
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.

6.438 × 10⁹⁵(96-digit number)
64387922174001874347…28810549215448888319
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
6.438 × 10⁹⁵(96-digit number)
64387922174001874347…28810549215448888319
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
1.287 × 10⁹⁶(97-digit number)
12877584434800374869…57621098430897776639
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
2.575 × 10⁹⁶(97-digit number)
25755168869600749739…15242196861795553279
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
5.151 × 10⁹⁶(97-digit number)
51510337739201499478…30484393723591106559
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
1.030 × 10⁹⁷(98-digit number)
10302067547840299895…60968787447182213119
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
2.060 × 10⁹⁷(98-digit number)
20604135095680599791…21937574894364426239
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
4.120 × 10⁹⁷(98-digit number)
41208270191361199582…43875149788728852479
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
8.241 × 10⁹⁷(98-digit number)
82416540382722399164…87750299577457704959
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
1.648 × 10⁹⁸(99-digit number)
16483308076544479832…75500599154915409919
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
3.296 × 10⁹⁸(99-digit number)
32966616153088959665…51001198309830819839
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
11
2^10 × origin − 1
6.593 × 10⁹⁸(99-digit number)
65933232306177919331…02002396619661639679
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:57,910,378 XPM·at block #6,833,272 · updates every 60s
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