1. #6,792,8701CC10 primes

    Cunningham 1st · ⛏️ coinsforall.io

Block #134,453

2CCLength 9★☆☆☆☆

Cunningham Chain of the Second Kind · Discovered 8/26/2013, 1:25:00 AM · Difficulty 9.8046 · 6,658,417 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
d72932006b25bf81fffd289a8ced7bd18f35094431ece0dcf12cf16d28586631

Height

#134,453

Difficulty

9.804598

Transactions

6

Size

1.30 KB

Version

2

Bits

09cdfa1f

Nonce

24,735

Timestamp

8/26/2013, 1:25:00 AM

Confirmations

6,658,417

Merkle Root

d06e3a4f87a6d5befbdd17d8e0f56818ea0309df7a407105282a8da2bdeeecd5
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.

3.507 × 10⁹²(93-digit number)
35074372578432077913…37637052623911889201
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
3.507 × 10⁹²(93-digit number)
35074372578432077913…37637052623911889201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
7.014 × 10⁹²(93-digit number)
70148745156864155827…75274105247823778401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.402 × 10⁹³(94-digit number)
14029749031372831165…50548210495647556801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.805 × 10⁹³(94-digit number)
28059498062745662330…01096420991295113601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
5.611 × 10⁹³(94-digit number)
56118996125491324661…02192841982590227201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.122 × 10⁹⁴(95-digit number)
11223799225098264932…04385683965180454401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.244 × 10⁹⁴(95-digit number)
22447598450196529864…08771367930360908801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
4.489 × 10⁹⁴(95-digit number)
44895196900393059729…17542735860721817601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
8.979 × 10⁹⁴(95-digit number)
89790393800786119458…35085471721443635201
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 9 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
CommonChain length 9

Found in most blocks. The baseline for Primecoin's proof-of-work.

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:57,586,936 XPM·at block #6,792,869 · updates every 60s
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