Block #2,866,299

1CCLength 11★★★☆☆

Cunningham Chain of the First Kind · Discovered 10/4/2018, 3:13:19 AM · Difficulty 11.6675 · 3,965,790 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
2c1cb7e152a1a299bf0845b1088d17e6a4ba91e401b7b3fb64f99e14cd32cb6e

Height

#2,866,299

Difficulty

11.667530

Transactions

3

Size

4.18 KB

Version

2

Bits

0baae346

Nonce

45,406,805

Timestamp

10/4/2018, 3:13:19 AM

Confirmations

3,965,790

Merkle Root

f06e262e5006f4740effcc0449f787228f3c26084b15bff290ab8a6f96e8ca69
Transactions (3)
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.

2.027 × 10⁹⁶(97-digit number)
20274598224685820327…50353046430246973439
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
2.027 × 10⁹⁶(97-digit number)
20274598224685820327…50353046430246973439
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
4.054 × 10⁹⁶(97-digit number)
40549196449371640655…00706092860493946879
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
8.109 × 10⁹⁶(97-digit number)
81098392898743281311…01412185720987893759
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
1.621 × 10⁹⁷(98-digit number)
16219678579748656262…02824371441975787519
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
3.243 × 10⁹⁷(98-digit number)
32439357159497312524…05648742883951575039
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
6.487 × 10⁹⁷(98-digit number)
64878714318994625049…11297485767903150079
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
1.297 × 10⁹⁸(99-digit number)
12975742863798925009…22594971535806300159
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
2.595 × 10⁹⁸(99-digit number)
25951485727597850019…45189943071612600319
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
5.190 × 10⁹⁸(99-digit number)
51902971455195700039…90379886143225200639
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
1.038 × 10⁹⁹(100-digit number)
10380594291039140007…80759772286450401279
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
11
2^10 × origin − 1
2.076 × 10⁹⁹(100-digit number)
20761188582078280015…61519544572900802559
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:57,900,840 XPM·at block #6,832,088 · updates every 60s
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