Block #858,134

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 12/18/2014, 9:09:46 AM · Difficulty 10.9671 · 5,986,420 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
b945af06a09e176c9c2fd3700c33cea20bba3eda8d5ce5395fa1b91142853c01

Height

#858,134

Difficulty

10.967068

Transactions

17

Size

4.10 KB

Version

2

Bits

0af791be

Nonce

593,135,647

Timestamp

12/18/2014, 9:09:46 AM

Confirmations

5,986,420

Merkle Root

4a61e108cf0860079a560bc375e48e9a9ecc500be92d8425eb8d84a795b142c3
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.

2.392 × 10⁹⁵(96-digit number)
23926393510204077162…04564507779757595201
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
2.392 × 10⁹⁵(96-digit number)
23926393510204077162…04564507779757595201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
4.785 × 10⁹⁵(96-digit number)
47852787020408154325…09129015559515190401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
9.570 × 10⁹⁵(96-digit number)
95705574040816308650…18258031119030380801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.914 × 10⁹⁶(97-digit number)
19141114808163261730…36516062238060761601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
3.828 × 10⁹⁶(97-digit number)
38282229616326523460…73032124476121523201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
7.656 × 10⁹⁶(97-digit number)
76564459232653046920…46064248952243046401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.531 × 10⁹⁷(98-digit number)
15312891846530609384…92128497904486092801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
3.062 × 10⁹⁷(98-digit number)
30625783693061218768…84256995808972185601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
6.125 × 10⁹⁷(98-digit number)
61251567386122437536…68513991617944371201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.225 × 10⁹⁸(99-digit number)
12250313477224487507…37027983235888742401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
2.450 × 10⁹⁸(99-digit number)
24500626954448975014…74055966471777484801
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:58,000,834 XPM·at block #6,844,553 · updates every 60s
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