Block #858,482

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/18/2014, 3:59:22 PM · Difficulty 10.9667 · 5,986,092 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
b3d6df233bb4f5be59e3e35c1c1fbe62a33e58b75e212688c7993ef38e12e863

Height

#858,482

Difficulty

10.966667

Transactions

7

Size

1.70 KB

Version

2

Bits

0af77783

Nonce

523,992,582

Timestamp

12/18/2014, 3:59:22 PM

Confirmations

5,986,092

Merkle Root

585fc40d11531ae45f75b7c45cec78c2a44ea273805b2b776fa327c44bb18d92
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.

2.407 × 10⁹⁵(96-digit number)
24074552947704802209…35496873828251508241
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
2.407 × 10⁹⁵(96-digit number)
24074552947704802209…35496873828251508241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
4.814 × 10⁹⁵(96-digit number)
48149105895409604418…70993747656503016481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
9.629 × 10⁹⁵(96-digit number)
96298211790819208836…41987495313006032961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.925 × 10⁹⁶(97-digit number)
19259642358163841767…83974990626012065921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
3.851 × 10⁹⁶(97-digit number)
38519284716327683534…67949981252024131841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
7.703 × 10⁹⁶(97-digit number)
77038569432655367069…35899962504048263681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.540 × 10⁹⁷(98-digit number)
15407713886531073413…71799925008096527361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
3.081 × 10⁹⁷(98-digit number)
30815427773062146827…43599850016193054721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
6.163 × 10⁹⁷(98-digit number)
61630855546124293655…87199700032386109441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.232 × 10⁹⁸(99-digit number)
12326171109224858731…74399400064772218881
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:58,000,997 XPM·at block #6,844,573 · updates every 60s
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