Block #322,929

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/21/2013, 8:20:33 AM · Difficulty 10.1949 · 6,476,389 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
8b2882ed7487f78cf7193ead64459fdef5f53c0ed60f2aef98619a1de510cc00

Height

#322,929

Difficulty

10.194924

Transactions

16

Size

16.68 KB

Version

2

Bits

0a31e68a

Nonce

967

Timestamp

12/21/2013, 8:20:33 AM

Confirmations

6,476,389

Merkle Root

58fe74479046f93accb156a12aae57623457b95801adf63296da69b568cd41a0
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.

6.185 × 10¹⁰¹(102-digit number)
61850025789105012720…78627969342564372481
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
6.185 × 10¹⁰¹(102-digit number)
61850025789105012720…78627969342564372481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.237 × 10¹⁰²(103-digit number)
12370005157821002544…57255938685128744961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.474 × 10¹⁰²(103-digit number)
24740010315642005088…14511877370257489921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
4.948 × 10¹⁰²(103-digit number)
49480020631284010176…29023754740514979841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
9.896 × 10¹⁰²(103-digit number)
98960041262568020352…58047509481029959681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.979 × 10¹⁰³(104-digit number)
19792008252513604070…16095018962059919361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
3.958 × 10¹⁰³(104-digit number)
39584016505027208141…32190037924119838721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
7.916 × 10¹⁰³(104-digit number)
79168033010054416282…64380075848239677441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.583 × 10¹⁰⁴(105-digit number)
15833606602010883256…28760151696479354881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
3.166 × 10¹⁰⁴(105-digit number)
31667213204021766512…57520303392958709761
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:57,638,592 XPM·at block #6,799,317 · updates every 60s
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