Block #285,494

TWNLength 10★★☆☆☆

Bi-Twin Chain · Discovered 11/30/2013, 12:37:20 PM · Difficulty 9.9844 · 6,521,371 confirmations

TWN
Bi-Twin Chain

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

Block Header
Block Hash
272c3a9de962b71f037821c77d7f53a344b3cd18a4b9806f8d4310e298d5997c

Height

#285,494

Difficulty

9.984359

Transactions

13

Size

4.22 KB

Version

2

Bits

09fbfeef

Nonce

75,394

Timestamp

11/30/2013, 12:37:20 PM

Confirmations

6,521,371

Merkle Root

7fe0dba849051ffcde8813a2ebd1ae78cc8fcba83063fad76e0f5fda1cbc5d69
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.

1.190 × 10⁹⁴(95-digit number)
11904858587252797686…04759540707347242239
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
1.190 × 10⁹⁴(95-digit number)
11904858587252797686…04759540707347242239
Verify on FactorDB ↗Wolfram Alpha ↗
origin + 1
1.190 × 10⁹⁴(95-digit number)
11904858587252797686…04759540707347242241
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
2.380 × 10⁹⁴(95-digit number)
23809717174505595372…09519081414694484479
Verify on FactorDB ↗Wolfram Alpha ↗
2^1 × origin + 1
2.380 × 10⁹⁴(95-digit number)
23809717174505595372…09519081414694484481
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
4.761 × 10⁹⁴(95-digit number)
47619434349011190745…19038162829388968959
Verify on FactorDB ↗Wolfram Alpha ↗
2^2 × origin + 1
4.761 × 10⁹⁴(95-digit number)
47619434349011190745…19038162829388968961
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
9.523 × 10⁹⁴(95-digit number)
95238868698022381490…38076325658777937919
Verify on FactorDB ↗Wolfram Alpha ↗
2^3 × origin + 1
9.523 × 10⁹⁴(95-digit number)
95238868698022381490…38076325658777937921
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
1.904 × 10⁹⁵(96-digit number)
19047773739604476298…76152651317555875839
Verify on FactorDB ↗Wolfram Alpha ↗
2^4 × origin + 1
1.904 × 10⁹⁵(96-digit number)
19047773739604476298…76152651317555875841
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:57,699,027 XPM·at block #6,806,864 · updates every 60s
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