Block #333,483

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/28/2013, 7:57:31 PM · Difficulty 10.1616 · 6,474,788 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
62089f4bd70f0acc61361ef738906745bc8b0897c8b2a5fa4e0f0746dbfca4b2

Height

#333,483

Difficulty

10.161584

Transactions

8

Size

2.99 KB

Version

2

Bits

0a295d8d

Nonce

23,769

Timestamp

12/28/2013, 7:57:31 PM

Confirmations

6,474,788

Merkle Root

724b6be4991f9743fb8f2a9b6733d57ade30f374d4672f26403c3ce400128936
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.

1.979 × 10⁹⁷(98-digit number)
19799225022761737330…85681720145446920961
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
1.979 × 10⁹⁷(98-digit number)
19799225022761737330…85681720145446920961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
3.959 × 10⁹⁷(98-digit number)
39598450045523474660…71363440290893841921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
7.919 × 10⁹⁷(98-digit number)
79196900091046949321…42726880581787683841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.583 × 10⁹⁸(99-digit number)
15839380018209389864…85453761163575367681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
3.167 × 10⁹⁸(99-digit number)
31678760036418779728…70907522327150735361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
6.335 × 10⁹⁸(99-digit number)
63357520072837559457…41815044654301470721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.267 × 10⁹⁹(100-digit number)
12671504014567511891…83630089308602941441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.534 × 10⁹⁹(100-digit number)
25343008029135023782…67260178617205882881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
5.068 × 10⁹⁹(100-digit number)
50686016058270047565…34520357234411765761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.013 × 10¹⁰⁰(101-digit number)
10137203211654009513…69040714468823531521
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:57,710,217 XPM·at block #6,808,270 · updates every 60s
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