Block #497,516

TWNLength 10★★☆☆☆

Bi-Twin Chain · Discovered 4/17/2014, 3:36:21 PM · Difficulty 10.7679 · 6,305,911 confirmations

TWN
Bi-Twin Chain

Interleaved pairs of primes that differ by 2, forming twin prime pairs at each level.

Block Header
Block Hash
820a77c8ff6c24028f15b8104e3cee1b11d57a37bbc7c6ab5702555b55c06c76

Height

#497,516

Difficulty

10.767929

Transactions

9

Size

2.72 KB

Version

2

Bits

0ac496f8

Nonce

234,876,996

Timestamp

4/17/2014, 3:36:21 PM

Confirmations

6,305,911

Merkle Root

8cf43a8dfc9f76f14528450e9f439e8c3b9e6eec7c2e2c563cc519da9282863f
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.

9.204 × 10⁹⁷(98-digit number)
92043618907698582800…97472684577176221599
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
9.204 × 10⁹⁷(98-digit number)
92043618907698582800…97472684577176221599
Verify on FactorDB ↗Wolfram Alpha ↗
origin + 1
9.204 × 10⁹⁷(98-digit number)
92043618907698582800…97472684577176221601
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
1.840 × 10⁹⁸(99-digit number)
18408723781539716560…94945369154352443199
Verify on FactorDB ↗Wolfram Alpha ↗
2^1 × origin + 1
1.840 × 10⁹⁸(99-digit number)
18408723781539716560…94945369154352443201
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
3.681 × 10⁹⁸(99-digit number)
36817447563079433120…89890738308704886399
Verify on FactorDB ↗Wolfram Alpha ↗
2^2 × origin + 1
3.681 × 10⁹⁸(99-digit number)
36817447563079433120…89890738308704886401
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
7.363 × 10⁹⁸(99-digit number)
73634895126158866240…79781476617409772799
Verify on FactorDB ↗Wolfram Alpha ↗
2^3 × origin + 1
7.363 × 10⁹⁸(99-digit number)
73634895126158866240…79781476617409772801
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
1.472 × 10⁹⁹(100-digit number)
14726979025231773248…59562953234819545599
Verify on FactorDB ↗Wolfram Alpha ↗
2^4 × origin + 1
1.472 × 10⁹⁹(100-digit number)
14726979025231773248…59562953234819545601
Verify on FactorDB ↗Wolfram Alpha ↗
Difference: 2^4 × origin + 1 − 2^4 × origin − 1 = 2 (twin primes ✓)

What this block proved

The miner who found this block proved the existence of 10 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
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 TWN formula:

TWN: twin pairs (p, p+2) where p = origin/primorial − 1 and p+2 = origin/primorial + 1
Circulating Supply:57,671,448 XPM·at block #6,803,426 · updates every 60s
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