Home/Chain Registry/Block #297,784

Block #297,784

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/6/2013, 7:54:12 PM · Difficulty 9.9920 · 6,501,055 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
121986d3d70ebe80fd9c88221c190b6c22c9d912ec14aa8a1e8abb7b59ed2972

Height

#297,784

Difficulty

9.992047

Transactions

11

Size

2.37 KB

Version

2

Bits

09fdf6c9

Nonce

202,733

Timestamp

12/6/2013, 7:54:12 PM

Confirmations

6,501,055

Merkle Root

e4acfe734e8c736386369c1dd7e9f515b64b1266955ba9c6b0b4fef800ec733e
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.

4.822 × 10⁹¹(92-digit number)
48225852584365515879…28202122106129773070
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
4.822 × 10⁹¹(92-digit number)
48225852584365515879…28202122106129773071
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
9.645 × 10⁹¹(92-digit number)
96451705168731031759…56404244212259546141
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.929 × 10⁹²(93-digit number)
19290341033746206351…12808488424519092281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
3.858 × 10⁹²(93-digit number)
38580682067492412703…25616976849038184561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
7.716 × 10⁹²(93-digit number)
77161364134984825407…51233953698076369121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.543 × 10⁹³(94-digit number)
15432272826996965081…02467907396152738241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
3.086 × 10⁹³(94-digit number)
30864545653993930163…04935814792305476481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
6.172 × 10⁹³(94-digit number)
61729091307987860326…09871629584610952961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.234 × 10⁹⁴(95-digit number)
12345818261597572065…19743259169221905921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.469 × 10⁹⁴(95-digit number)
24691636523195144130…39486518338443811841
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 Second 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
UncommonChain length 10
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 2CC formula:

2CC: 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 297784

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 121986d3d70ebe80fd9c88221c190b6c22c9d912ec14aa8a1e8abb7b59ed2972

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 #297,784 on Chainz ↗
Circulating Supply:57,634,744 XPM·at block #6,798,838 · updates every 60s
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