Block #177,008

1CCLength 9★☆☆☆☆

Cunningham Chain of the First Kind · Discovered 9/23/2013, 8:40:26 AM · Difficulty 9.8652 · 6,626,738 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
a3b9cdbab6f00a16129e9cdf1d12dbc9052b44cb18d5a8b419d0fcd8a716d239

Height

#177,008

Difficulty

9.865167

Transactions

7

Size

2.73 KB

Version

2

Bits

09dd7b8f

Nonce

21,783

Timestamp

9/23/2013, 8:40:26 AM

Confirmations

6,626,738

Merkle Root

0c21fe08b2d0e75a4447281d2c2e4effd458f433e093e1b1151f9c98b9532209
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.

6.046 × 10⁹²(93-digit number)
60466021263994665048…10144778100025743359
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
6.046 × 10⁹²(93-digit number)
60466021263994665048…10144778100025743359
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
1.209 × 10⁹³(94-digit number)
12093204252798933009…20289556200051486719
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
2.418 × 10⁹³(94-digit number)
24186408505597866019…40579112400102973439
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
4.837 × 10⁹³(94-digit number)
48372817011195732038…81158224800205946879
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
9.674 × 10⁹³(94-digit number)
96745634022391464076…62316449600411893759
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
1.934 × 10⁹⁴(95-digit number)
19349126804478292815…24632899200823787519
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
3.869 × 10⁹⁴(95-digit number)
38698253608956585630…49265798401647575039
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
7.739 × 10⁹⁴(95-digit number)
77396507217913171261…98531596803295150079
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
1.547 × 10⁹⁵(96-digit number)
15479301443582634252…97063193606590300159
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 9 consecutive prime numbers forming a Cunningham Chain of the First 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
CommonChain length 9

Found in most blocks. The baseline for Primecoin's proof-of-work.

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 1CC formula:

1CC: p₁ (first prime), p₂ = 2p₁ + 1, p₃ = 2p₂ + 1, …
Circulating Supply:57,674,006 XPM·at block #6,803,745 · updates every 60s
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