Block #437,326

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 3/10/2014, 5:35:04 AM · Difficulty 10.3582 · 6,369,384 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
32b8dd68768778ad3756d360c8f9b7abbfca67ae3b536c9f8d7a4d871bfa4a66

Height

#437,326

Difficulty

10.358180

Transactions

3

Size

1.47 KB

Version

2

Bits

0a5bb1aa

Nonce

97,148

Timestamp

3/10/2014, 5:35:04 AM

Confirmations

6,369,384

Merkle Root

984d541c7b127280a610574552bf675916e3dec264732bfd6b691c87daea4438
Transactions (3)
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.

1.369 × 10¹⁰⁰(101-digit number)
13692687872645366928…21753315605749339501
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
1.369 × 10¹⁰⁰(101-digit number)
13692687872645366928…21753315605749339501
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.738 × 10¹⁰⁰(101-digit number)
27385375745290733856…43506631211498679001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
5.477 × 10¹⁰⁰(101-digit number)
54770751490581467713…87013262422997358001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.095 × 10¹⁰¹(102-digit number)
10954150298116293542…74026524845994716001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.190 × 10¹⁰¹(102-digit number)
21908300596232587085…48053049691989432001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
4.381 × 10¹⁰¹(102-digit number)
43816601192465174170…96106099383978864001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
8.763 × 10¹⁰¹(102-digit number)
87633202384930348341…92212198767957728001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.752 × 10¹⁰²(103-digit number)
17526640476986069668…84424397535915456001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
3.505 × 10¹⁰²(103-digit number)
35053280953972139336…68848795071830912001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
7.010 × 10¹⁰²(103-digit number)
70106561907944278672…37697590143661824001
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:57,697,778 XPM·at block #6,806,709 · updates every 60s
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