1. #6,803,8912CC11 primes

    Cunningham 2nd · ⛏️ coinsforall.io

Block #334,838

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/29/2013, 6:46:04 PM · Difficulty 10.1595 · 6,469,054 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
c107ff8dba6b07f5a4fc98d77141cdf2df8f51a997a8243bd4b426c3b1beb5b7

Height

#334,838

Difficulty

10.159506

Transactions

6

Size

1.54 KB

Version

2

Bits

0a28d564

Nonce

52,437

Timestamp

12/29/2013, 6:46:04 PM

Confirmations

6,469,054

Merkle Root

f8f7b737a1adc60bb69140adfa8495c26b09b16f9bc7921e3c91833d21debda7
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.

3.732 × 10⁹⁶(97-digit number)
37321224173589994885…13673722891621607861
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
3.732 × 10⁹⁶(97-digit number)
37321224173589994885…13673722891621607861
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
7.464 × 10⁹⁶(97-digit number)
74642448347179989771…27347445783243215721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.492 × 10⁹⁷(98-digit number)
14928489669435997954…54694891566486431441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.985 × 10⁹⁷(98-digit number)
29856979338871995908…09389783132972862881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
5.971 × 10⁹⁷(98-digit number)
59713958677743991817…18779566265945725761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.194 × 10⁹⁸(99-digit number)
11942791735548798363…37559132531891451521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.388 × 10⁹⁸(99-digit number)
23885583471097596726…75118265063782903041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
4.777 × 10⁹⁸(99-digit number)
47771166942195193453…50236530127565806081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
9.554 × 10⁹⁸(99-digit number)
95542333884390386907…00473060255131612161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.910 × 10⁹⁹(100-digit number)
19108466776878077381…00946120510263224321
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:57,675,180 XPM·at block #6,803,891 · updates every 60s
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