Block #82,483

1CCLength 9★☆☆☆☆

Cunningham Chain of the First Kind · Discovered 7/25/2013, 11:15:33 AM · Difficulty 9.2745 · 6,733,763 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
5581f15842890070ab7ca798da34207da3d7199053128421aa1ae33fae53cf4d

Height

#82,483

Difficulty

9.274451

Transactions

4

Size

1.38 KB

Version

2

Bits

0946426e

Nonce

1,509

Timestamp

7/25/2013, 11:15:33 AM

Confirmations

6,733,763

Merkle Root

e7235c17df8b51e2a2b6c94dc7c6cfc68123c0375d266af92cca261559d41e8a
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.

7.182 × 10¹¹⁰(111-digit number)
71821365942232536499…94580465751281668279
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
7.182 × 10¹¹⁰(111-digit number)
71821365942232536499…94580465751281668279
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
1.436 × 10¹¹¹(112-digit number)
14364273188446507299…89160931502563336559
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
2.872 × 10¹¹¹(112-digit number)
28728546376893014599…78321863005126673119
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
5.745 × 10¹¹¹(112-digit number)
57457092753786029199…56643726010253346239
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
1.149 × 10¹¹²(113-digit number)
11491418550757205839…13287452020506692479
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
2.298 × 10¹¹²(113-digit number)
22982837101514411679…26574904041013384959
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
4.596 × 10¹¹²(113-digit number)
45965674203028823359…53149808082026769919
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
9.193 × 10¹¹²(113-digit number)
91931348406057646719…06299616164053539839
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
1.838 × 10¹¹³(114-digit number)
18386269681211529343…12599232328107079679
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 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
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 1CC formula:

1CC: p₁ (first prime), p₂ = 2p₁ + 1, p₃ = 2p₂ + 1, …
Circulating Supply:57,774,087 XPM·at block #6,816,245 · updates every 60s
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