Block #464,827

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 3/29/2014, 1:15:58 AM · Difficulty 10.4227 · 6,345,311 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
8fd69b5b51fa72a462211d5cd7f17acb9469dbc0cb31c6f05c3ab10f4dabe692

Height

#464,827

Difficulty

10.422744

Transactions

2

Size

1.59 KB

Version

2

Bits

0a6c38f0

Nonce

161,912

Timestamp

3/29/2014, 1:15:58 AM

Confirmations

6,345,311

Merkle Root

fe7b40f53f4e3dce475f76bdd5e50cdd4bc775e6995994e4ad2eda963798378a
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.

7.864 × 10⁹⁷(98-digit number)
78648780507194420547…74237850336187940401
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
7.864 × 10⁹⁷(98-digit number)
78648780507194420547…74237850336187940401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.572 × 10⁹⁸(99-digit number)
15729756101438884109…48475700672375880801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
3.145 × 10⁹⁸(99-digit number)
31459512202877768219…96951401344751761601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
6.291 × 10⁹⁸(99-digit number)
62919024405755536438…93902802689503523201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.258 × 10⁹⁹(100-digit number)
12583804881151107287…87805605379007046401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.516 × 10⁹⁹(100-digit number)
25167609762302214575…75611210758014092801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
5.033 × 10⁹⁹(100-digit number)
50335219524604429150…51222421516028185601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.006 × 10¹⁰⁰(101-digit number)
10067043904920885830…02444843032056371201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.013 × 10¹⁰⁰(101-digit number)
20134087809841771660…04889686064112742401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
4.026 × 10¹⁰⁰(101-digit number)
40268175619683543320…09779372128225484801
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:57,725,172 XPM·at block #6,810,137 · updates every 60s
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