Home/Chain Registry/Block #517,563

Block #517,563

TWNLength 10★★☆☆☆

Bi-Twin Chain · Discovered 4/30/2014, 1:04:54 AM · Difficulty 10.8514 · 6,276,509 confirmations

TWN

Bi-Twin Chain

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

Block Header

Block Hash

820c665a61eee50d9f7792a43360d746f1a1cff833f7cf5a426885d01aa36c81

View on Chainz ↗

Height

#517,563

Difficulty

10.851428

Transactions

Size

208 B

Version

Bits

0ad9f72e

Nonce

4,827,691

Timestamp

4/30/2014, 1:04:54 AM

Confirmations

6,276,509

Merkle Root

ec79a53ed4b564ad178d85bd7517f71d953893a517e4892df2a3fa3481619500

Transactions (1)

Coinbaseec79a53ed4b564…a3fa3481619500

1 in → 1 out8.4800 XPM116 B

AbwWkWZt…kawDhufa

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.

7.510 × 10⁹⁹(100-digit number)

75108151248210822422…21387071169205548800

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

7.510 × 10⁹⁹(100-digit number)

75108151248210822422…21387071169205548799

Verify on FactorDB ↗Wolfram Alpha ↗

origin + 1

7.510 × 10⁹⁹(100-digit number)

75108151248210822422…21387071169205548801

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

1.502 × 10¹⁰⁰(101-digit number)

15021630249642164484…42774142338411097599

Verify on FactorDB ↗Wolfram Alpha ↗

2^1 × origin + 1

1.502 × 10¹⁰⁰(101-digit number)

15021630249642164484…42774142338411097601

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

3.004 × 10¹⁰⁰(101-digit number)

30043260499284328968…85548284676822195199

Verify on FactorDB ↗Wolfram Alpha ↗

2^2 × origin + 1

3.004 × 10¹⁰⁰(101-digit number)

30043260499284328968…85548284676822195201

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

6.008 × 10¹⁰⁰(101-digit number)

60086520998568657937…71096569353644390399

Verify on FactorDB ↗Wolfram Alpha ↗

2^3 × origin + 1

6.008 × 10¹⁰⁰(101-digit number)

60086520998568657937…71096569353644390401

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

1.201 × 10¹⁰¹(102-digit number)

12017304199713731587…42193138707288780799

Verify on FactorDB ↗Wolfram Alpha ↗

2^4 × origin + 1

1.201 × 10¹⁰¹(102-digit number)

12017304199713731587…42193138707288780801

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.

View full Prime Chain Discovery page →

★★☆☆☆

Rarity

UncommonChain length 10

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

Verify on a Primecoin Node

Anyone running a Primecoin node can independently verify this block using the following RPC commands. Run these from the primecoin-cli command line or via the debug console in the Primecoin wallet.

1. Get block hash by height

getblockhash 517563

Returns the block hash for a given block height. Use this to confirm the hash shown above matches the chain.

2. Get full block data

getblock 820c665a61eee50d9f7792a43360d746f1a1cff833f7cf5a426885d01aa36c81

Returns the full block header including difficulty, prime chain origin, prime chain type, transaction IDs, and all other fields shown on this page.

How to run these commands: To verify this data independently, open a terminal on your own Primecoin node and run primecoin-cli <command>. Alternatively, open the Primecoin-Qt wallet, go to Help → Debug Window → Console, and type the command directly. The node must be fully synced to this block height for the commands to return results.

Cross-reference on Chainz Explorer

Chainz is an independent Primecoin block explorer. Compare this block's data to verify accuracy.

View Block #517,563 on Chainz ↗