Home/Chain Registry/Block #263,608

Block #263,608

TWNLength 10★★☆☆☆

Bi-Twin Chain · Discovered 11/17/2013, 11:54:10 PM · Difficulty 9.9657 · 6,537,262 confirmations

TWN
Bi-Twin Chain

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

Block Header
Block Hash
a1d4c542a3ff90faf46edff00718489032bc13bd7ea5e8dffd35deaa6607dab3

Height

#263,608

Difficulty

9.965660

Transactions

8

Size

2.50 KB

Version

2

Bits

09f73578

Nonce

2,671

Timestamp

11/17/2013, 11:54:10 PM

Confirmations

6,537,262

Merkle Root

6a5a140c398489e6b16893c26d90afc6a33e86bca3c4ea8aa64803e066472bdc
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.

4.598 × 10⁹³(94-digit number)
45980604929087808486…50663679048802958060
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
4.598 × 10⁹³(94-digit number)
45980604929087808486…50663679048802958059
Verify on FactorDB ↗Wolfram Alpha ↗
origin + 1
4.598 × 10⁹³(94-digit number)
45980604929087808486…50663679048802958061
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
9.196 × 10⁹³(94-digit number)
91961209858175616972…01327358097605916119
Verify on FactorDB ↗Wolfram Alpha ↗
2^1 × origin + 1
9.196 × 10⁹³(94-digit number)
91961209858175616972…01327358097605916121
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
1.839 × 10⁹⁴(95-digit number)
18392241971635123394…02654716195211832239
Verify on FactorDB ↗Wolfram Alpha ↗
2^2 × origin + 1
1.839 × 10⁹⁴(95-digit number)
18392241971635123394…02654716195211832241
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
3.678 × 10⁹⁴(95-digit number)
36784483943270246788…05309432390423664479
Verify on FactorDB ↗Wolfram Alpha ↗
2^3 × origin + 1
3.678 × 10⁹⁴(95-digit number)
36784483943270246788…05309432390423664481
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
7.356 × 10⁹⁴(95-digit number)
73568967886540493577…10618864780847328959
Verify on FactorDB ↗Wolfram Alpha ↗
2^4 × origin + 1
7.356 × 10⁹⁴(95-digit number)
73568967886540493577…10618864780847328961
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 263608

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 a1d4c542a3ff90faf46edff00718489032bc13bd7ea5e8dffd35deaa6607dab3

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 #263,608 on Chainz ↗
Circulating Supply:57,651,016 XPM·at block #6,800,869 · updates every 60s
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