Block #2,807,209

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.

2.646 × 10⁹⁷(98-digit number)

26463842316927214013…95352066390415061759

Discovered Prime Numbers

Lower: 2^k × origin − 1 | Upper: 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.

Level 0 — Twin Prime Pair (origin ± 1)

origin − 1

2.646 × 10⁹⁷(98-digit number)

26463842316927214013…95352066390415061759

Verify on FactorDB ↗Wolfram Alpha ↗

origin + 1

2.646 × 10⁹⁷(98-digit number)

26463842316927214013…95352066390415061761

Verify on FactorDB ↗Wolfram Alpha ↗

Difference: origin + 1 − origin − 1 = 2 (twin primes ✓)

Level 1 — Twin Prime Pair (2^1 × origin ± 1)

2^1 × origin − 1

5.292 × 10⁹⁷(98-digit number)

52927684633854428027…90704132780830123519

Verify on FactorDB ↗Wolfram Alpha ↗

2^1 × origin + 1

5.292 × 10⁹⁷(98-digit number)

52927684633854428027…90704132780830123521

Verify on FactorDB ↗Wolfram Alpha ↗

Difference: 2^1 × origin + 1 − 2^1 × origin − 1 = 2 (twin primes ✓)

Level 2 — Twin Prime Pair (2^2 × origin ± 1)

2^2 × origin − 1

1.058 × 10⁹⁸(99-digit number)

10585536926770885605…81408265561660247039

Verify on FactorDB ↗Wolfram Alpha ↗

2^2 × origin + 1

1.058 × 10⁹⁸(99-digit number)

10585536926770885605…81408265561660247041

Verify on FactorDB ↗Wolfram Alpha ↗

Difference: 2^2 × origin + 1 − 2^2 × origin − 1 = 2 (twin primes ✓)

Level 3 — Twin Prime Pair (2^3 × origin ± 1)

2^3 × origin − 1

2.117 × 10⁹⁸(99-digit number)

21171073853541771211…62816531123320494079

Verify on FactorDB ↗Wolfram Alpha ↗

2^3 × origin + 1

2.117 × 10⁹⁸(99-digit number)

21171073853541771211…62816531123320494081

Verify on FactorDB ↗Wolfram Alpha ↗

Difference: 2^3 × origin + 1 − 2^3 × origin − 1 = 2 (twin primes ✓)

Level 4 — Twin Prime Pair (2^4 × origin ± 1)

2^4 × origin − 1

4.234 × 10⁹⁸(99-digit number)

42342147707083542422…25633062246640988159

Verify on FactorDB ↗Wolfram Alpha ↗

2^4 × origin + 1

4.234 × 10⁹⁸(99-digit number)

42342147707083542422…25633062246640988161

Verify on FactorDB ↗Wolfram Alpha ↗

Difference: 2^4 × origin + 1 − 2^4 × origin − 1 = 2 (twin primes ✓)

Level 5 — Twin Prime Pair (2^5 × origin ± 1)

2^5 × origin − 1

8.468 × 10⁹⁸(99-digit number)

84684295414167084844…51266124493281976319

Verify on FactorDB ↗Wolfram Alpha ↗

2^5 × origin + 1

8.468 × 10⁹⁸(99-digit number)

84684295414167084844…51266124493281976321

Verify on FactorDB ↗Wolfram Alpha ↗

Difference: 2^5 × origin + 1 − 2^5 × origin − 1 = 2 (twin primes ✓)

What this block proved

The miner who found this block proved the existence of 12 consecutive prime numbers forming a Bi-Twin Chain. 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 TWN formula:

TWN: twin pairs (p, p+2) where p = origin/primorial − 1 and p+2 = origin/primorial + 1

Cross-reference on Chainz Explorer

Block #2,807,209

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