Block #322,894

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/21/2013, 7:55:14 AM · Difficulty 10.1938 · 6,482,466 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
d4a0b25a146f13ceb91405944556ca9430b4b67ec04e22e0d194ef0c1193ee09

Height

#322,894

Difficulty

10.193825

Transactions

8

Size

3.21 KB

Version

2

Bits

0a319e7c

Nonce

14,944

Timestamp

12/21/2013, 7:55:14 AM

Confirmations

6,482,466

Merkle Root

58eb4b1f40537190edf4210ca14c443ad2422ed8c9296f8c31d291d0e24532a7
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.

2.799 × 10¹⁰⁰(101-digit number)
27992643397307801059…99913298869615319041
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
2.799 × 10¹⁰⁰(101-digit number)
27992643397307801059…99913298869615319041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
5.598 × 10¹⁰⁰(101-digit number)
55985286794615602119…99826597739230638081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.119 × 10¹⁰¹(102-digit number)
11197057358923120423…99653195478461276161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.239 × 10¹⁰¹(102-digit number)
22394114717846240847…99306390956922552321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
4.478 × 10¹⁰¹(102-digit number)
44788229435692481695…98612781913845104641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
8.957 × 10¹⁰¹(102-digit number)
89576458871384963391…97225563827690209281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.791 × 10¹⁰²(103-digit number)
17915291774276992678…94451127655380418561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
3.583 × 10¹⁰²(103-digit number)
35830583548553985356…88902255310760837121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
7.166 × 10¹⁰²(103-digit number)
71661167097107970713…77804510621521674241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.433 × 10¹⁰³(104-digit number)
14332233419421594142…55609021243043348481
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:57,686,953 XPM·at block #6,805,359 · updates every 60s
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