Block #325,004

1CCLength 10★★☆☆☆

Cunningham Chain of the First Kind · Discovered 12/22/2013, 5:35:37 PM · Difficulty 10.2077 · 6,485,133 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
78aba41ec19193d6fe55a2fbdb37908fbb1a401ceae27415d81d6f3f2331e4fb

Height

#325,004

Difficulty

10.207734

Transactions

16

Size

3.93 KB

Version

2

Bits

0a352e12

Nonce

14,972

Timestamp

12/22/2013, 5:35:37 PM

Confirmations

6,485,133

Merkle Root

640c67287d79107e669a5bca695fd28824136384ee37cb5e45b1dc04f9bfb4e5
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.

1.326 × 10¹⁰³(104-digit number)
13266692245580467189…48502285285202279679
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
1.326 × 10¹⁰³(104-digit number)
13266692245580467189…48502285285202279679
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
2.653 × 10¹⁰³(104-digit number)
26533384491160934379…97004570570404559359
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
5.306 × 10¹⁰³(104-digit number)
53066768982321868758…94009141140809118719
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
1.061 × 10¹⁰⁴(105-digit number)
10613353796464373751…88018282281618237439
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
2.122 × 10¹⁰⁴(105-digit number)
21226707592928747503…76036564563236474879
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
4.245 × 10¹⁰⁴(105-digit number)
42453415185857495006…52073129126472949759
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
8.490 × 10¹⁰⁴(105-digit number)
84906830371714990013…04146258252945899519
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
1.698 × 10¹⁰⁵(106-digit number)
16981366074342998002…08292516505891799039
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
3.396 × 10¹⁰⁵(106-digit number)
33962732148685996005…16585033011783598079
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
6.792 × 10¹⁰⁵(106-digit number)
67925464297371992011…33170066023567196159
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 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
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 1CC formula:

1CC: p₁ (first prime), p₂ = 2p₁ + 1, p₃ = 2p₂ + 1, …
Circulating Supply:57,725,164 XPM·at block #6,810,136 · updates every 60s
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