Block #510,752

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 4/25/2014, 8:22:25 PM · Difficulty 10.8265 · 6,288,187 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
7736740ac8704209ac257453faccacf1718a5e846f69c2e015ec8c3ffee86439

Height

#510,752

Difficulty

10.826528

Transactions

15

Size

3.95 KB

Version

2

Bits

0ad3974f

Nonce

77,962,834

Timestamp

4/25/2014, 8:22:25 PM

Confirmations

6,288,187

Merkle Root

32a70a4343a28133dbc5c173de456e0e17bbda32c221cbffc9493c3a2cc283ea
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.

6.966 × 10⁹⁸(99-digit number)
69666567859530370860…02385559007861604001
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
6.966 × 10⁹⁸(99-digit number)
69666567859530370860…02385559007861604001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.393 × 10⁹⁹(100-digit number)
13933313571906074172…04771118015723208001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.786 × 10⁹⁹(100-digit number)
27866627143812148344…09542236031446416001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
5.573 × 10⁹⁹(100-digit number)
55733254287624296688…19084472062892832001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.114 × 10¹⁰⁰(101-digit number)
11146650857524859337…38168944125785664001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.229 × 10¹⁰⁰(101-digit number)
22293301715049718675…76337888251571328001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
4.458 × 10¹⁰⁰(101-digit number)
44586603430099437350…52675776503142656001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
8.917 × 10¹⁰⁰(101-digit number)
89173206860198874701…05351553006285312001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.783 × 10¹⁰¹(102-digit number)
17834641372039774940…10703106012570624001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
3.566 × 10¹⁰¹(102-digit number)
35669282744079549880…21406212025141248001
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:57,635,548 XPM·at block #6,798,938 · updates every 60s
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