Block #329,778

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/26/2013, 5:22:25 AM · Difficulty 10.1682 · 6,477,358 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
74ade5166c44e7239c19bcc474c9f67ae6de6b862cb38736ea6416a51c15328a

Height

#329,778

Difficulty

10.168164

Transactions

13

Size

4.03 KB

Version

2

Bits

0a2b0cd2

Nonce

50,017

Timestamp

12/26/2013, 5:22:25 AM

Confirmations

6,477,358

Merkle Root

b1189330cef8680c737a8e6d0ef3bdba750a12850f5a784b43434a64322f2380
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.

4.594 × 10⁹⁸(99-digit number)
45943630185648681668…84138861109590220801
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
4.594 × 10⁹⁸(99-digit number)
45943630185648681668…84138861109590220801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
9.188 × 10⁹⁸(99-digit number)
91887260371297363336…68277722219180441601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.837 × 10⁹⁹(100-digit number)
18377452074259472667…36555444438360883201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
3.675 × 10⁹⁹(100-digit number)
36754904148518945334…73110888876721766401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
7.350 × 10⁹⁹(100-digit number)
73509808297037890669…46221777753443532801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.470 × 10¹⁰⁰(101-digit number)
14701961659407578133…92443555506887065601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.940 × 10¹⁰⁰(101-digit number)
29403923318815156267…84887111013774131201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
5.880 × 10¹⁰⁰(101-digit number)
58807846637630312535…69774222027548262401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.176 × 10¹⁰¹(102-digit number)
11761569327526062507…39548444055096524801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.352 × 10¹⁰¹(102-digit number)
23523138655052125014…79096888110193049601
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:57,701,193 XPM·at block #6,807,135 · updates every 60s
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