Block #524,376

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 5/4/2014, 3:48:20 AM · Difficulty 10.8758 · 6,283,873 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
5f187f56bc7f2251b359a4d442d183541cedf6efe133550cd35d22cf49df884f

Height

#524,376

Difficulty

10.875750

Transactions

6

Size

2.63 KB

Version

2

Bits

0ae0312a

Nonce

700,631,034

Timestamp

5/4/2014, 3:48:20 AM

Confirmations

6,283,873

Merkle Root

3110d82a815bdd8ac70b3cdb80d45e3f9134199009484c764c1a8e390cdc141d
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.

5.570 × 10⁸⁹(90-digit number)
55709793158167569033…77588350764758356301
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
5.570 × 10⁸⁹(90-digit number)
55709793158167569033…77588350764758356301
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.114 × 10⁹⁰(91-digit number)
11141958631633513806…55176701529516712601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.228 × 10⁹⁰(91-digit number)
22283917263267027613…10353403059033425201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
4.456 × 10⁹⁰(91-digit number)
44567834526534055226…20706806118066850401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
8.913 × 10⁹⁰(91-digit number)
89135669053068110453…41413612236133700801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.782 × 10⁹¹(92-digit number)
17827133810613622090…82827224472267401601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
3.565 × 10⁹¹(92-digit number)
35654267621227244181…65654448944534803201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
7.130 × 10⁹¹(92-digit number)
71308535242454488363…31308897889069606401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.426 × 10⁹²(93-digit number)
14261707048490897672…62617795778139212801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.852 × 10⁹²(93-digit number)
28523414096981795345…25235591556278425601
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:57,710,037 XPM·at block #6,808,248 · updates every 60s
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