Block #94,786

2CCLength 9★☆☆☆☆

Cunningham Chain of the Second Kind · Discovered 8/3/2013, 7:40:50 AM · Difficulty 9.2088 · 6,722,112 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
d9ba05017ea14a70bf43060619dc9d15eecf3bfb867d2648b15395c33f82b0c3

Height

#94,786

Difficulty

9.208830

Transactions

10

Size

2.89 KB

Version

2

Bits

093575e5

Nonce

77,635

Timestamp

8/3/2013, 7:40:50 AM

Confirmations

6,722,112

Merkle Root

4adf6f4310a59f93ba2996664acd5a360d6e1a7890704e986a21a4c461f6b539
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.

4.083 × 10¹¹⁶(117-digit number)
40837142066004695252…11211540539006352681
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
4.083 × 10¹¹⁶(117-digit number)
40837142066004695252…11211540539006352681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
8.167 × 10¹¹⁶(117-digit number)
81674284132009390504…22423081078012705361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.633 × 10¹¹⁷(118-digit number)
16334856826401878100…44846162156025410721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
3.266 × 10¹¹⁷(118-digit number)
32669713652803756201…89692324312050821441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
6.533 × 10¹¹⁷(118-digit number)
65339427305607512403…79384648624101642881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.306 × 10¹¹⁸(119-digit number)
13067885461121502480…58769297248203285761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.613 × 10¹¹⁸(119-digit number)
26135770922243004961…17538594496406571521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
5.227 × 10¹¹⁸(119-digit number)
52271541844486009922…35077188992813143041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.045 × 10¹¹⁹(120-digit number)
10454308368897201984…70154377985626286081
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 9 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
CommonChain length 9

Found in most blocks. The baseline for Primecoin's proof-of-work.

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:57,779,226 XPM·at block #6,816,897 · updates every 60s
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