Block #384,152

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/31/2014, 9:53:05 PM · Difficulty 10.4034 · 6,412,733 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
b6c9731f22165124c77b652551fd58dcb9a2d8f53b68e7d2e193189ef3b8102d

Height

#384,152

Difficulty

10.403432

Transactions

2

Size

433 B

Version

2

Bits

0a67474f

Nonce

5,994

Timestamp

1/31/2014, 9:53:05 PM

Confirmations

6,412,733

Merkle Root

43bf225813e70459248e647e556953df9ac29218a0484faf87ec8aef596f2009
Transactions (2)
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.

5.160 × 10⁹⁷(98-digit number)
51607334794416684668…86086596591312612801
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
5.160 × 10⁹⁷(98-digit number)
51607334794416684668…86086596591312612801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.032 × 10⁹⁸(99-digit number)
10321466958883336933…72173193182625225601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.064 × 10⁹⁸(99-digit number)
20642933917766673867…44346386365250451201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
4.128 × 10⁹⁸(99-digit number)
41285867835533347734…88692772730500902401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
8.257 × 10⁹⁸(99-digit number)
82571735671066695469…77385545461001804801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.651 × 10⁹⁹(100-digit number)
16514347134213339093…54771090922003609601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
3.302 × 10⁹⁹(100-digit number)
33028694268426678187…09542181844007219201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
6.605 × 10⁹⁹(100-digit number)
66057388536853356375…19084363688014438401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.321 × 10¹⁰⁰(101-digit number)
13211477707370671275…38168727376028876801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.642 × 10¹⁰⁰(101-digit number)
26422955414741342550…76337454752057753601
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:57,619,098 XPM·at block #6,796,884 · updates every 60s
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