Block #325,147

1CCLength 10★★☆☆☆

Cunningham Chain of the First Kind · Discovered 12/22/2013, 8:05:40 PM · Difficulty 10.2071 · 6,477,523 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
a21d61b615f2397ae9ea0cc950ece8f3d8c043675773147a8619decc545d9465

Height

#325,147

Difficulty

10.207141

Transactions

9

Size

1.90 KB

Version

2

Bits

0a350729

Nonce

787,290

Timestamp

12/22/2013, 8:05:40 PM

Confirmations

6,477,523

Merkle Root

1b0a99ddd4e29ebb83aeeedf38fa4f4aced8e5e01ba0d5d05165a97d1e54d40e
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.

4.362 × 10⁹⁴(95-digit number)
43626716030473122566…39586741594652806399
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
4.362 × 10⁹⁴(95-digit number)
43626716030473122566…39586741594652806399
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
8.725 × 10⁹⁴(95-digit number)
87253432060946245132…79173483189305612799
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
1.745 × 10⁹⁵(96-digit number)
17450686412189249026…58346966378611225599
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
3.490 × 10⁹⁵(96-digit number)
34901372824378498053…16693932757222451199
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
6.980 × 10⁹⁵(96-digit number)
69802745648756996106…33387865514444902399
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
1.396 × 10⁹⁶(97-digit number)
13960549129751399221…66775731028889804799
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
2.792 × 10⁹⁶(97-digit number)
27921098259502798442…33551462057779609599
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
5.584 × 10⁹⁶(97-digit number)
55842196519005596884…67102924115559219199
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
1.116 × 10⁹⁷(98-digit number)
11168439303801119376…34205848231118438399
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
2.233 × 10⁹⁷(98-digit number)
22336878607602238753…68411696462236876799
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:57,665,380 XPM·at block #6,802,669 · updates every 60s
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