Block #322,263

1CCLength 10★★☆☆☆

Cunningham Chain of the First Kind · Discovered 12/20/2013, 8:49:50 PM · Difficulty 10.1984 · 6,486,297 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
7206eb68137333ccb6d187736c30f41f0de0d0d8341856c226947df69e16d572

Height

#322,263

Difficulty

10.198439

Transactions

28

Size

7.84 KB

Version

2

Bits

0a32cceb

Nonce

58,065

Timestamp

12/20/2013, 8:49:50 PM

Confirmations

6,486,297

Merkle Root

c4ed3a9cb068a1d31f2bf5f03a557cf6942d95e00d0da41566e517150a9f716e
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.

3.665 × 10⁹⁷(98-digit number)
36652662388497638000…35474125297305773279
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
3.665 × 10⁹⁷(98-digit number)
36652662388497638000…35474125297305773279
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
7.330 × 10⁹⁷(98-digit number)
73305324776995276001…70948250594611546559
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
1.466 × 10⁹⁸(99-digit number)
14661064955399055200…41896501189223093119
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
2.932 × 10⁹⁸(99-digit number)
29322129910798110400…83793002378446186239
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
5.864 × 10⁹⁸(99-digit number)
58644259821596220801…67586004756892372479
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
1.172 × 10⁹⁹(100-digit number)
11728851964319244160…35172009513784744959
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
2.345 × 10⁹⁹(100-digit number)
23457703928638488320…70344019027569489919
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
4.691 × 10⁹⁹(100-digit number)
46915407857276976641…40688038055138979839
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
9.383 × 10⁹⁹(100-digit number)
93830815714553953282…81376076110277959679
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
1.876 × 10¹⁰⁰(101-digit number)
18766163142910790656…62752152220555919359
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:57,712,538 XPM·at block #6,808,559 · updates every 60s
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