Block #502,805

1CCLength 10★★☆☆☆

Cunningham Chain of the First Kind · Discovered 4/20/2014, 4:16:24 PM · Difficulty 10.8081 · 6,306,342 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
e165da0fbb627a74ecf55b07a5bf27fa07d8b2bfce3b96e273a4664572677b6a

Height

#502,805

Difficulty

10.808069

Transactions

5

Size

2.93 KB

Version

2

Bits

0acedd9b

Nonce

374,047

Timestamp

4/20/2014, 4:16:24 PM

Confirmations

6,306,342

Merkle Root

b8364582b91cb6c3a08eb77f727da8613ac8390d8fa0c0aa0be23db6f7c750b5
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.

7.345 × 10⁹⁸(99-digit number)
73453657163755763691…07639235174512180159
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
7.345 × 10⁹⁸(99-digit number)
73453657163755763691…07639235174512180159
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
1.469 × 10⁹⁹(100-digit number)
14690731432751152738…15278470349024360319
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
2.938 × 10⁹⁹(100-digit number)
29381462865502305476…30556940698048720639
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
5.876 × 10⁹⁹(100-digit number)
58762925731004610953…61113881396097441279
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
1.175 × 10¹⁰⁰(101-digit number)
11752585146200922190…22227762792194882559
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
2.350 × 10¹⁰⁰(101-digit number)
23505170292401844381…44455525584389765119
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
4.701 × 10¹⁰⁰(101-digit number)
47010340584803688762…88911051168779530239
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
9.402 × 10¹⁰⁰(101-digit number)
94020681169607377525…77822102337559060479
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
1.880 × 10¹⁰¹(102-digit number)
18804136233921475505…55644204675118120959
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
3.760 × 10¹⁰¹(102-digit number)
37608272467842951010…11288409350236241919
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:57,717,238 XPM·at block #6,809,146 · updates every 60s
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