Block #237,134

TWNLength 9★☆☆☆☆

Bi-Twin Chain · Discovered 10/31/2013, 9:06:50 PM · Difficulty 9.9492 · 6,578,793 confirmations

TWN
Bi-Twin Chain

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

Block Header
Block Hash
b717f6c0c28e4b8864f43f20f8dde468fde420ec17a634b9eae61c2acae5c8bf

Height

#237,134

Difficulty

9.949163

Transactions

8

Size

1.67 KB

Version

2

Bits

09f2fc55

Nonce

28,752

Timestamp

10/31/2013, 9:06:50 PM

Confirmations

6,578,793

Merkle Root

fb7d2dd582160ed512285d3a2e84342c1e6a4aa6a2e00629cc929e866a842156
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.

1.089 × 10¹⁰²(103-digit number)
10894471740166592224…94521660532936437759
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
1.089 × 10¹⁰²(103-digit number)
10894471740166592224…94521660532936437759
Verify on FactorDB ↗Wolfram Alpha ↗
origin + 1
1.089 × 10¹⁰²(103-digit number)
10894471740166592224…94521660532936437761
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
2.178 × 10¹⁰²(103-digit number)
21788943480333184449…89043321065872875519
Verify on FactorDB ↗Wolfram Alpha ↗
2^1 × origin + 1
2.178 × 10¹⁰²(103-digit number)
21788943480333184449…89043321065872875521
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
4.357 × 10¹⁰²(103-digit number)
43577886960666368899…78086642131745751039
Verify on FactorDB ↗Wolfram Alpha ↗
2^2 × origin + 1
4.357 × 10¹⁰²(103-digit number)
43577886960666368899…78086642131745751041
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
8.715 × 10¹⁰²(103-digit number)
87155773921332737798…56173284263491502079
Verify on FactorDB ↗Wolfram Alpha ↗
2^3 × origin + 1
8.715 × 10¹⁰²(103-digit number)
87155773921332737798…56173284263491502081
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
1.743 × 10¹⁰³(104-digit number)
17431154784266547559…12346568526983004159
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 9 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
CommonChain length 9

Found in most blocks. The baseline for Primecoin's proof-of-work.

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:57,771,528 XPM·at block #6,815,926 · updates every 60s
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