Block #367,293

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/19/2014, 11:35:46 PM · Difficulty 10.4356 · 6,438,676 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
fbf3bff9f6fd015e971f5da524c9430cbc8e05fb5e7f75ba084ed9a89cbf2396

Height

#367,293

Difficulty

10.435563

Transactions

2

Size

1.23 KB

Version

2

Bits

0a6f810b

Nonce

58,096

Timestamp

1/19/2014, 11:35:46 PM

Confirmations

6,438,676

Merkle Root

24150f0a313b404b3b0b8e3c727f5d6f8334d2a542eade03fb5fa0fe512b8bfa
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.

4.870 × 10⁹²(93-digit number)
48700372417814238203…87223155592871128961
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
4.870 × 10⁹²(93-digit number)
48700372417814238203…87223155592871128961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
9.740 × 10⁹²(93-digit number)
97400744835628476407…74446311185742257921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.948 × 10⁹³(94-digit number)
19480148967125695281…48892622371484515841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
3.896 × 10⁹³(94-digit number)
38960297934251390562…97785244742969031681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
7.792 × 10⁹³(94-digit number)
77920595868502781125…95570489485938063361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.558 × 10⁹⁴(95-digit number)
15584119173700556225…91140978971876126721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
3.116 × 10⁹⁴(95-digit number)
31168238347401112450…82281957943752253441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
6.233 × 10⁹⁴(95-digit number)
62336476694802224900…64563915887504506881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.246 × 10⁹⁵(96-digit number)
12467295338960444980…29127831775009013761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.493 × 10⁹⁵(96-digit number)
24934590677920889960…58255663550018027521
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:57,691,826 XPM·at block #6,805,968 · updates every 60s
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