Block #6,784,938

1CCLength 11★★★☆☆

Cunningham Chain of the First Kind · Discovered 4/5/2026, 11:02:56 PM · Difficulty 10.9809 · 216 confirmations

1CC

Cunningham Chain of the First Kind

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

Block Header

Block Hash

734a222dfbd4e5d1f61199c9f212f641a363b410fd31ac4ec46d4d53859ab38b

View on Chainz ↗

Height

#6,784,938

Difficulty

10.980861

Transactions

Size

192 B

Version

536870912

Bits

0afb19ba

Nonce

1,788,853,094

Timestamp

4/5/2026, 11:02:56 PM

Confirmations

216

Merkle Root

8d8298e0dad88fcb0fe8479385a9943c696eafd75b27e6f10a7d8f1bffba77a6

Transactions (1)

Coinbase8d8298e0dad88f…7d8f1bffba77a6

1 in → 1 out8.1790 XPM101 B

AMrLYUQN…jwjifxiz

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.

2.811 × 10⁹⁶(97-digit number)

28118107904505071001…09884204741623270399

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.

origin − 1

2.811 × 10⁹⁶(97-digit number)

28118107904505071001…09884204741623270399

Verify on FactorDB ↗Wolfram Alpha ↗

×2+1 →

2^1 × origin − 1

5.623 × 10⁹⁶(97-digit number)

56236215809010142002…19768409483246540799

Verify on FactorDB ↗Wolfram Alpha ↗

×2+1 →

2^2 × origin − 1

1.124 × 10⁹⁷(98-digit number)

11247243161802028400…39536818966493081599

Verify on FactorDB ↗Wolfram Alpha ↗

×2+1 →

2^3 × origin − 1

2.249 × 10⁹⁷(98-digit number)

22494486323604056800…79073637932986163199

Verify on FactorDB ↗Wolfram Alpha ↗

×2+1 →

2^4 × origin − 1

4.498 × 10⁹⁷(98-digit number)

44988972647208113601…58147275865972326399

Verify on FactorDB ↗Wolfram Alpha ↗

×2+1 →

2^5 × origin − 1

8.997 × 10⁹⁷(98-digit number)

89977945294416227203…16294551731944652799

Verify on FactorDB ↗Wolfram Alpha ↗

×2+1 →

2^6 × origin − 1

1.799 × 10⁹⁸(99-digit number)

17995589058883245440…32589103463889305599

Verify on FactorDB ↗Wolfram Alpha ↗

×2+1 →

2^7 × origin − 1

3.599 × 10⁹⁸(99-digit number)

35991178117766490881…65178206927778611199

Verify on FactorDB ↗Wolfram Alpha ↗

×2+1 →

2^8 × origin − 1

7.198 × 10⁹⁸(99-digit number)

71982356235532981763…30356413855557222399

Verify on FactorDB ↗Wolfram Alpha ↗

×2+1 →

2^9 × origin − 1

1.439 × 10⁹⁹(100-digit number)

14396471247106596352…60712827711114444799

Verify on FactorDB ↗Wolfram Alpha ↗

×2+1 →

2^10 × origin − 1

2.879 × 10⁹⁹(100-digit number)

28792942494213192705…21425655422228889599

Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 11 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

RareChain length 11

Approximately 1 in 1,000 blocks. Noteworthy discoveries.

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, …

Cross-reference on Chainz Explorer