Block #335,322

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/30/2013, 3:32:13 AM · Difficulty 10.1530 · 6,465,893 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
2eb43d9f634ed71dd6102219f0f97738d8a836fca04668672a1ad795651fa50f

Height

#335,322

Difficulty

10.153046

Transactions

19

Size

19.88 KB

Version

2

Bits

0a272e0e

Nonce

172,948

Timestamp

12/30/2013, 3:32:13 AM

Confirmations

6,465,893

Merkle Root

f995d6eac5c7a46884ce74efe3db2763d4559233f80d100228a726735710b2c2
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.

7.187 × 10¹⁰¹(102-digit number)
71874536536332944367…81003905105187155201
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
7.187 × 10¹⁰¹(102-digit number)
71874536536332944367…81003905105187155201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.437 × 10¹⁰²(103-digit number)
14374907307266588873…62007810210374310401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.874 × 10¹⁰²(103-digit number)
28749814614533177747…24015620420748620801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
5.749 × 10¹⁰²(103-digit number)
57499629229066355494…48031240841497241601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.149 × 10¹⁰³(104-digit number)
11499925845813271098…96062481682994483201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.299 × 10¹⁰³(104-digit number)
22999851691626542197…92124963365988966401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
4.599 × 10¹⁰³(104-digit number)
45999703383253084395…84249926731977932801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
9.199 × 10¹⁰³(104-digit number)
91999406766506168790…68499853463955865601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.839 × 10¹⁰⁴(105-digit number)
18399881353301233758…36999706927911731201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
3.679 × 10¹⁰⁴(105-digit number)
36799762706602467516…73999413855823462401
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:57,653,783 XPM·at block #6,801,214 · updates every 60s
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