Block #267,043

1CCLength 10★★☆☆☆

Cunningham Chain of the First Kind · Discovered 11/20/2013, 10:25:26 PM · Difficulty 9.9599 · 6,525,127 confirmations

1CC
Cunningham Chain of the First Kind

A sequence where each prime is double the previous prime plus one.

Block Header
Block Hash
afe74be91a90b594e12a95b254560f6744d3684bb8367c89ec0a9d220d5a8cad

Height

#267,043

Difficulty

9.959942

Transactions

12

Size

3.38 KB

Version

2

Bits

09f5bec8

Nonce

15,518

Timestamp

11/20/2013, 10:25:26 PM

Confirmations

6,525,127

Merkle Root

4f2e5f53bccd735f3d1134c0a0f6aef4569160256c46e3cc944717c9e820b494
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.

4.586 × 10¹⁰¹(102-digit number)
45863568329567699027…01723261486153035199
Discovered Prime Numbers
p_k = 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.

1
origin − 1
4.586 × 10¹⁰¹(102-digit number)
45863568329567699027…01723261486153035199
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
9.172 × 10¹⁰¹(102-digit number)
91727136659135398054…03446522972306070399
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
1.834 × 10¹⁰²(103-digit number)
18345427331827079610…06893045944612140799
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
3.669 × 10¹⁰²(103-digit number)
36690854663654159221…13786091889224281599
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
7.338 × 10¹⁰²(103-digit number)
73381709327308318443…27572183778448563199
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
1.467 × 10¹⁰³(104-digit number)
14676341865461663688…55144367556897126399
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
2.935 × 10¹⁰³(104-digit number)
29352683730923327377…10288735113794252799
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
5.870 × 10¹⁰³(104-digit number)
58705367461846654754…20577470227588505599
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
1.174 × 10¹⁰⁴(105-digit number)
11741073492369330950…41154940455177011199
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
2.348 × 10¹⁰⁴(105-digit number)
23482146984738661901…82309880910354022399
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 10 consecutive prime numbers forming a Cunningham Chain of the First Kind. 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 1CC formula:

1CC: p₁ (first prime), p₂ = 2p₁ + 1, p₃ = 2p₂ + 1, …
Circulating Supply:57,581,315 XPM·at block #6,792,169 · updates every 60s
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