Block #844,000

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.

7.943 × 10⁹⁶(97-digit number)

79437278097297473876…68607832031446502401

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

7.943 × 10⁹⁶(97-digit number)

79437278097297473876…68607832031446502401

Verify on FactorDB ↗Wolfram Alpha ↗

×2−1 →

2^1 × origin + 1

1.588 × 10⁹⁷(98-digit number)

15887455619459494775…37215664062893004801

Verify on FactorDB ↗Wolfram Alpha ↗

×2−1 →

2^2 × origin + 1

3.177 × 10⁹⁷(98-digit number)

31774911238918989550…74431328125786009601

Verify on FactorDB ↗Wolfram Alpha ↗

×2−1 →

2^3 × origin + 1

6.354 × 10⁹⁷(98-digit number)

63549822477837979101…48862656251572019201

Verify on FactorDB ↗Wolfram Alpha ↗

×2−1 →

2^4 × origin + 1

1.270 × 10⁹⁸(99-digit number)

12709964495567595820…97725312503144038401

Verify on FactorDB ↗Wolfram Alpha ↗

×2−1 →

2^5 × origin + 1

2.541 × 10⁹⁸(99-digit number)

25419928991135191640…95450625006288076801

Verify on FactorDB ↗Wolfram Alpha ↗

×2−1 →

2^6 × origin + 1

5.083 × 10⁹⁸(99-digit number)

50839857982270383281…90901250012576153601

Verify on FactorDB ↗Wolfram Alpha ↗

×2−1 →

2^7 × origin + 1

1.016 × 10⁹⁹(100-digit number)

10167971596454076656…81802500025152307201

Verify on FactorDB ↗Wolfram Alpha ↗

×2−1 →

2^8 × origin + 1

2.033 × 10⁹⁹(100-digit number)

20335943192908153312…63605000050304614401

Verify on FactorDB ↗Wolfram Alpha ↗

×2−1 →

2^9 × origin + 1

4.067 × 10⁹⁹(100-digit number)

40671886385816306624…27210000100609228801

Verify on FactorDB ↗Wolfram Alpha ↗

×2−1 →

2^10 × origin + 1

8.134 × 10⁹⁹(100-digit number)

81343772771632613249…54420000201218457601

Verify on FactorDB ↗Wolfram Alpha ↗

×2−1 →

2^11 × origin + 1

1.626 × 10¹⁰⁰(101-digit number)

16268754554326522649…08840000402436915201

Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 12 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

ExceptionalChain length 12

Around 1 in 10,000 blocks. A significant mathematical achievement.

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, …

Cross-reference on Chainz Explorer

Block #844,000

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