Block #26,041

1CCLength 8★☆☆☆☆

Cunningham Chain of the First Kind · Discovered 7/13/2013, 4:07:28 AM · Difficulty 7.9735 · 6,781,094 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
000b3f33d9a7f38ecc3ec82cf7ecc573de71d1f48567a0421dfb960870d2b380

Height

#26,041

Difficulty

7.973528

Transactions

9

Size

3.40 KB

Version

2

Bits

07f93926

Nonce

279

Timestamp

7/13/2013, 4:07:28 AM

Confirmations

6,781,094

Merkle Root

dd88efdd165339740eb4dbbbe35bdddd83af7270dda9b606fcc51623fe1fa61d
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.

5.047 × 10⁹⁷(98-digit number)
50479781928659926161…35234852321674832399
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
5.047 × 10⁹⁷(98-digit number)
50479781928659926161…35234852321674832399
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
1.009 × 10⁹⁸(99-digit number)
10095956385731985232…70469704643349664799
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
2.019 × 10⁹⁸(99-digit number)
20191912771463970464…40939409286699329599
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
4.038 × 10⁹⁸(99-digit number)
40383825542927940929…81878818573398659199
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
8.076 × 10⁹⁸(99-digit number)
80767651085855881858…63757637146797318399
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
1.615 × 10⁹⁹(100-digit number)
16153530217171176371…27515274293594636799
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
3.230 × 10⁹⁹(100-digit number)
32307060434342352743…55030548587189273599
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
6.461 × 10⁹⁹(100-digit number)
64614120868684705486…10061097174378547199
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 8 consecutive prime numbers forming a Cunningham Chain of the First 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 8

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 1CC formula:

1CC: p₁ (first prime), p₂ = 2p₁ + 1, p₃ = 2p₂ + 1, …
Circulating Supply:57,701,185 XPM·at block #6,807,134 · updates every 60s
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