Block #494,529

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 4/16/2014, 5:20:23 AM · Difficulty 10.7203 · 6,308,887 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
706c15676e2c344810c773d0bb3fd0c0a9e41532d87f6f3b5cc06e474f7d515e

Height

#494,529

Difficulty

10.720268

Transactions

17

Size

4.75 KB

Version

2

Bits

0ab8637a

Nonce

170,166,764

Timestamp

4/16/2014, 5:20:23 AM

Confirmations

6,308,887

Merkle Root

0b065218f81778410e6ecdcab4f220dd2ff3cec59c9baeec8b7ed01254f67094
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.

3.226 × 10⁹⁹(100-digit number)
32260604052395543734…34061930654925209601
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
3.226 × 10⁹⁹(100-digit number)
32260604052395543734…34061930654925209601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
6.452 × 10⁹⁹(100-digit number)
64521208104791087469…68123861309850419201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.290 × 10¹⁰⁰(101-digit number)
12904241620958217493…36247722619700838401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.580 × 10¹⁰⁰(101-digit number)
25808483241916434987…72495445239401676801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
5.161 × 10¹⁰⁰(101-digit number)
51616966483832869975…44990890478803353601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.032 × 10¹⁰¹(102-digit number)
10323393296766573995…89981780957606707201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.064 × 10¹⁰¹(102-digit number)
20646786593533147990…79963561915213414401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
4.129 × 10¹⁰¹(102-digit number)
41293573187066295980…59927123830426828801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
8.258 × 10¹⁰¹(102-digit number)
82587146374132591961…19854247660853657601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.651 × 10¹⁰²(103-digit number)
16517429274826518392…39708495321707315201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
3.303 × 10¹⁰²(103-digit number)
33034858549653036784…79416990643414630401
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 11 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
RareChain length 11

Approximately 1 in 1,000 blocks. Noteworthy discoveries.

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:57,671,359 XPM·at block #6,803,415 · updates every 60s
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