Block #500,595

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 4/19/2014, 6:08:52 AM · Difficulty 10.8011 · 6,295,261 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
a5fefdf24c26e6b505cc3cae7a78f361bf2751fba1e86f3f4e7bf66b9acae166

Height

#500,595

Difficulty

10.801051

Transactions

4

Size

877 B

Version

2

Bits

0acd11ae

Nonce

19,216,431

Timestamp

4/19/2014, 6:08:52 AM

Confirmations

6,295,261

Merkle Root

99f1d71fa162f7a6a0e35a286f2eac096513ba8388f41d0c3ddc277ac97fd86a
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.

7.511 × 10⁹⁵(96-digit number)
75113744290565252219…87453851635334266241
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
7.511 × 10⁹⁵(96-digit number)
75113744290565252219…87453851635334266241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.502 × 10⁹⁶(97-digit number)
15022748858113050443…74907703270668532481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
3.004 × 10⁹⁶(97-digit number)
30045497716226100887…49815406541337064961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
6.009 × 10⁹⁶(97-digit number)
60090995432452201775…99630813082674129921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.201 × 10⁹⁷(98-digit number)
12018199086490440355…99261626165348259841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.403 × 10⁹⁷(98-digit number)
24036398172980880710…98523252330696519681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
4.807 × 10⁹⁷(98-digit number)
48072796345961761420…97046504661393039361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
9.614 × 10⁹⁷(98-digit number)
96145592691923522841…94093009322786078721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.922 × 10⁹⁸(99-digit number)
19229118538384704568…88186018645572157441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
3.845 × 10⁹⁸(99-digit number)
38458237076769409136…76372037291144314881
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:57,610,934 XPM·at block #6,795,855 · updates every 60s
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