Block #892,056

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/12/2015, 7:19:03 AM · Difficulty 10.9526 · 5,911,400 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
180bb7e4f2b738f498476289a3d6eb4a60289c95273d232c8be327bd4052b0b1

Height

#892,056

Difficulty

10.952623

Transactions

7

Size

1.82 KB

Version

2

Bits

0af3df18

Nonce

46,832,518

Timestamp

1/12/2015, 7:19:03 AM

Confirmations

5,911,400

Merkle Root

7cea4a8fcf24464bbe536d79d40e5933593cbff168d31fe94f9494647f0219b1
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.

1.259 × 10⁹⁸(99-digit number)
12597582399228505680…85267040146921984001
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
1.259 × 10⁹⁸(99-digit number)
12597582399228505680…85267040146921984001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.519 × 10⁹⁸(99-digit number)
25195164798457011361…70534080293843968001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
5.039 × 10⁹⁸(99-digit number)
50390329596914022722…41068160587687936001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.007 × 10⁹⁹(100-digit number)
10078065919382804544…82136321175375872001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.015 × 10⁹⁹(100-digit number)
20156131838765609089…64272642350751744001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
4.031 × 10⁹⁹(100-digit number)
40312263677531218178…28545284701503488001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
8.062 × 10⁹⁹(100-digit number)
80624527355062436356…57090569403006976001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.612 × 10¹⁰⁰(101-digit number)
16124905471012487271…14181138806013952001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
3.224 × 10¹⁰⁰(101-digit number)
32249810942024974542…28362277612027904001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
6.449 × 10¹⁰⁰(101-digit number)
64499621884049949085…56724555224055808001
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:57,671,675 XPM·at block #6,803,455 · updates every 60s
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