Block #325,044

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/22/2013, 6:13:24 PM · Difficulty 10.2083 · 6,491,737 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
9dc4d77a82c242f2d9f4ec55628b47b568e7416773eeb8b5c210e671533a6c3c

Height

#325,044

Difficulty

10.208317

Transactions

11

Size

3.27 KB

Version

2

Bits

0a35544a

Nonce

322,188

Timestamp

12/22/2013, 6:13:24 PM

Confirmations

6,491,737

Merkle Root

8847046ee9bc17883ab2fbdc905934fdec72d3f9d52842f239c7230fe7317b3e
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.

1.336 × 10⁹⁵(96-digit number)
13360372217969446083…04570030608824048001
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
1.336 × 10⁹⁵(96-digit number)
13360372217969446083…04570030608824048001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.672 × 10⁹⁵(96-digit number)
26720744435938892166…09140061217648096001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
5.344 × 10⁹⁵(96-digit number)
53441488871877784332…18280122435296192001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.068 × 10⁹⁶(97-digit number)
10688297774375556866…36560244870592384001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.137 × 10⁹⁶(97-digit number)
21376595548751113732…73120489741184768001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
4.275 × 10⁹⁶(97-digit number)
42753191097502227465…46240979482369536001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
8.550 × 10⁹⁶(97-digit number)
85506382195004454931…92481958964739072001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.710 × 10⁹⁷(98-digit number)
17101276439000890986…84963917929478144001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
3.420 × 10⁹⁷(98-digit number)
34202552878001781972…69927835858956288001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
6.840 × 10⁹⁷(98-digit number)
68405105756003563945…39855671717912576001
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:57,778,283 XPM·at block #6,816,780 · updates every 60s
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