Home/Chain Registry/Block #245,200

Block #245,200

1CCLength 9★☆☆☆☆

Cunningham Chain of the First Kind · Discovered 11/5/2013, 8:15:32 AM · Difficulty 9.9636 · 6,549,390 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
59eb9cf9e054cba5baae4ebb6448c3c3aa77dadaeb89b5870a3cfe31c169b438

Height

#245,200

Difficulty

9.963551

Transactions

7

Size

10.64 KB

Version

2

Bits

09f6ab4c

Nonce

8,611

Timestamp

11/5/2013, 8:15:32 AM

Confirmations

6,549,390

Merkle Root

3e5b1a345b84647368f5799ec8a17eec29acdacff51ad9db5e9f37ded0674eca
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.

1.609 × 10⁹⁹(100-digit number)
16092792845377924984…68510600648030774460
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
1.609 × 10⁹⁹(100-digit number)
16092792845377924984…68510600648030774459
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
3.218 × 10⁹⁹(100-digit number)
32185585690755849969…37021201296061548919
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
6.437 × 10⁹⁹(100-digit number)
64371171381511699938…74042402592123097839
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
1.287 × 10¹⁰⁰(101-digit number)
12874234276302339987…48084805184246195679
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
2.574 × 10¹⁰⁰(101-digit number)
25748468552604679975…96169610368492391359
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
5.149 × 10¹⁰⁰(101-digit number)
51496937105209359950…92339220736984782719
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
1.029 × 10¹⁰¹(102-digit number)
10299387421041871990…84678441473969565439
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
2.059 × 10¹⁰¹(102-digit number)
20598774842083743980…69356882947939130879
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
4.119 × 10¹⁰¹(102-digit number)
41197549684167487960…38713765895878261759
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.

View full Prime Chain Discovery page →
★☆☆☆☆
Rarity
CommonChain length 9
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, …
Verify on a Primecoin Node

Anyone running a Primecoin node can independently verify this block using the following RPC commands. Run these from the primecoin-cli command line or via the debug console in the Primecoin wallet.

1. Get block hash by height
getblockhash 245200

Returns the block hash for a given block height. Use this to confirm the hash shown above matches the chain.

2. Get full block data
getblock 59eb9cf9e054cba5baae4ebb6448c3c3aa77dadaeb89b5870a3cfe31c169b438

Returns the full block header including difficulty, prime chain origin, prime chain type, transaction IDs, and all other fields shown on this page.

How to run these commands: To verify this data independently, open a terminal on your own Primecoin node and run primecoin-cli <command>. Alternatively, open the Primecoin-Qt wallet, go to Help → Debug Window → Console, and type the command directly. The node must be fully synced to this block height for the commands to return results.

Cross-reference on Chainz Explorer

Chainz is an independent Primecoin block explorer. Compare this block's data to verify accuracy.

View Block #245,200 on Chainz ↗
Circulating Supply:57,600,760 XPM·at block #6,794,589 · updates every 60s
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