Block #446,215

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 3/16/2014, 9:55:34 AM · Difficulty 10.3617 · 6,351,662 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
cb04a938687f2c729da94408dfdc43a8a0d8b728c7a28d5e60e8d983031bfc69

Height

#446,215

Difficulty

10.361694

Transactions

3

Size

1.46 KB

Version

2

Bits

0a5c97f9

Nonce

410,570

Timestamp

3/16/2014, 9:55:34 AM

Confirmations

6,351,662

Merkle Root

9d3c3385b4f58d18de3a226938e1026556800eeb6418c1e2b04ad7aface1a1e6
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.

2.980 × 10⁹⁷(98-digit number)
29802755874675638985…20327677636923377201
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
2.980 × 10⁹⁷(98-digit number)
29802755874675638985…20327677636923377201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
5.960 × 10⁹⁷(98-digit number)
59605511749351277971…40655355273846754401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.192 × 10⁹⁸(99-digit number)
11921102349870255594…81310710547693508801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.384 × 10⁹⁸(99-digit number)
23842204699740511188…62621421095387017601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
4.768 × 10⁹⁸(99-digit number)
47684409399481022377…25242842190774035201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
9.536 × 10⁹⁸(99-digit number)
95368818798962044754…50485684381548070401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.907 × 10⁹⁹(100-digit number)
19073763759792408950…00971368763096140801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
3.814 × 10⁹⁹(100-digit number)
38147527519584817901…01942737526192281601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
7.629 × 10⁹⁹(100-digit number)
76295055039169635803…03885475052384563201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.525 × 10¹⁰⁰(101-digit number)
15259011007833927160…07770950104769126401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
3.051 × 10¹⁰⁰(101-digit number)
30518022015667854321…15541900209538252801
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 11 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
RareChain length 11

Approximately 1 in 1,000 blocks. Noteworthy discoveries.

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:57,627,005 XPM·at block #6,797,876 · updates every 60s
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