1. #6,806,5302CC11 primes

    Cunningham 2nd · ⛏️ coinsforall.io

Block #292,093

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/3/2013, 1:30:54 PM · Difficulty 9.9901 · 6,514,438 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
26e4042df863596311b9c6042bc111c361c3fa2dc9e10fd08f840ebe63f81f34

Height

#292,093

Difficulty

9.990121

Transactions

18

Size

5.66 KB

Version

2

Bits

09fd7894

Nonce

58,734

Timestamp

12/3/2013, 1:30:54 PM

Confirmations

6,514,438

Merkle Root

620a4a3af12bf3d57a9f23da5525f6af1cd16af3941f410d9b19e611ffd3e41e
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.

2.641 × 10⁹⁵(96-digit number)
26410442056719693885…20221375661023583921
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
2.641 × 10⁹⁵(96-digit number)
26410442056719693885…20221375661023583921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
5.282 × 10⁹⁵(96-digit number)
52820884113439387770…40442751322047167841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.056 × 10⁹⁶(97-digit number)
10564176822687877554…80885502644094335681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.112 × 10⁹⁶(97-digit number)
21128353645375755108…61771005288188671361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
4.225 × 10⁹⁶(97-digit number)
42256707290751510216…23542010576377342721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
8.451 × 10⁹⁶(97-digit number)
84513414581503020432…47084021152754685441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.690 × 10⁹⁷(98-digit number)
16902682916300604086…94168042305509370881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
3.380 × 10⁹⁷(98-digit number)
33805365832601208173…88336084611018741761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
6.761 × 10⁹⁷(98-digit number)
67610731665202416346…76672169222037483521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.352 × 10⁹⁸(99-digit number)
13522146333040483269…53344338444074967041
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 10 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
UncommonChain length 10

Roughly 1 in 100 blocks. Solid but expected in a healthy network.

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:57,696,347 XPM·at block #6,806,530 · updates every 60s
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