Home/Chain Registry/Block #302,319

Block #302,319

2CCLength 9★☆☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/9/2013, 6:02:49 PM · Difficulty 9.9927 · 6,493,806 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
6846c8a22c0b7331ec8498770bc1d50fe8db3e70779abd866397ba7c6c6cf443

Height

#302,319

Difficulty

9.992686

Transactions

10

Size

2.47 KB

Version

2

Bits

09fe20b3

Nonce

60,615

Timestamp

12/9/2013, 6:02:49 PM

Confirmations

6,493,806

Merkle Root

64b9eeb052582c582863ff833fd0856f4d54cd45bf43ce808221996e3131bc79
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.

1.367 × 10⁹⁴(95-digit number)
13675695029669804681…46794661040864672000
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
1.367 × 10⁹⁴(95-digit number)
13675695029669804681…46794661040864672001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.735 × 10⁹⁴(95-digit number)
27351390059339609363…93589322081729344001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
5.470 × 10⁹⁴(95-digit number)
54702780118679218727…87178644163458688001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.094 × 10⁹⁵(96-digit number)
10940556023735843745…74357288326917376001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.188 × 10⁹⁵(96-digit number)
21881112047471687490…48714576653834752001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
4.376 × 10⁹⁵(96-digit number)
43762224094943374981…97429153307669504001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
8.752 × 10⁹⁵(96-digit number)
87524448189886749963…94858306615339008001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.750 × 10⁹⁶(97-digit number)
17504889637977349992…89716613230678016001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
3.500 × 10⁹⁶(97-digit number)
35009779275954699985…79433226461356032001
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 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
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 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 302319

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 6846c8a22c0b7331ec8498770bc1d50fe8db3e70779abd866397ba7c6c6cf443

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 #302,319 on Chainz ↗
Circulating Supply:57,612,996 XPM·at block #6,796,124 · updates every 60s
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