Block #852,012

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/13/2014, 6:19:13 PM · Difficulty 10.9702 · 5,964,159 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
5eb5ab86550244b3bb324dfe65fc8043281bca22182c08cc04632e33e64565a2

Height

#852,012

Difficulty

10.970162

Transactions

5

Size

1.66 KB

Version

2

Bits

0af85c83

Nonce

1,543,418,121

Timestamp

12/13/2014, 6:19:13 PM

Confirmations

5,964,159

Merkle Root

efa949215f871e41e78528e3cbd9e095721153f125298b61530a3309ff44689a
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.

3.335 × 10⁹⁶(97-digit number)
33357369602165774433…73687096087419742721
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
3.335 × 10⁹⁶(97-digit number)
33357369602165774433…73687096087419742721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
6.671 × 10⁹⁶(97-digit number)
66714739204331548867…47374192174839485441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.334 × 10⁹⁷(98-digit number)
13342947840866309773…94748384349678970881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.668 × 10⁹⁷(98-digit number)
26685895681732619546…89496768699357941761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
5.337 × 10⁹⁷(98-digit number)
53371791363465239093…78993537398715883521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.067 × 10⁹⁸(99-digit number)
10674358272693047818…57987074797431767041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.134 × 10⁹⁸(99-digit number)
21348716545386095637…15974149594863534081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
4.269 × 10⁹⁸(99-digit number)
42697433090772191274…31948299189727068161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
8.539 × 10⁹⁸(99-digit number)
85394866181544382549…63896598379454136321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.707 × 10⁹⁹(100-digit number)
17078973236308876509…27793196758908272641
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:57,773,491 XPM·at block #6,816,170 · updates every 60s
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