Block #1,109,118

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 6/16/2015, 5:31:23 AM · Difficulty 10.8517 · 5,718,018 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
e828f32699a114ca483e38a8ec7bac6d9c403b1ee907196b5c1eac25f2ca131f

Height

#1,109,118

Difficulty

10.851725

Transactions

3

Size

35.04 KB

Version

2

Bits

0ada0a9f

Nonce

40,367,737

Timestamp

6/16/2015, 5:31:23 AM

Confirmations

5,718,018

Merkle Root

c369df00f3b028b280de40951e16d632776b958f0903b55a1b4555cdee7a1fa5
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.

7.157 × 10⁹⁴(95-digit number)
71571956591826385975…67806747577693703041
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
7.157 × 10⁹⁴(95-digit number)
71571956591826385975…67806747577693703041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.431 × 10⁹⁵(96-digit number)
14314391318365277195…35613495155387406081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.862 × 10⁹⁵(96-digit number)
28628782636730554390…71226990310774812161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
5.725 × 10⁹⁵(96-digit number)
57257565273461108780…42453980621549624321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.145 × 10⁹⁶(97-digit number)
11451513054692221756…84907961243099248641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.290 × 10⁹⁶(97-digit number)
22903026109384443512…69815922486198497281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
4.580 × 10⁹⁶(97-digit number)
45806052218768887024…39631844972396994561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
9.161 × 10⁹⁶(97-digit number)
91612104437537774048…79263689944793989121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.832 × 10⁹⁷(98-digit number)
18322420887507554809…58527379889587978241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
3.664 × 10⁹⁷(98-digit number)
36644841775015109619…17054759779175956481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
7.328 × 10⁹⁷(98-digit number)
73289683550030219238…34109519558351912961
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:57,861,269 XPM·at block #6,827,135 · updates every 60s
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