Home/Chain Registry/Block #302,944

Block #302,944

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/10/2013, 2:37:44 AM · Difficulty 9.9929 · 6,492,906 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
6ac76aa102c8508481edb67805b6306bd5e9ffbb18fbfcc1ad910b861680e3ff

Height

#302,944

Difficulty

9.992863

Transactions

11

Size

14.51 KB

Version

2

Bits

09fe2c4d

Nonce

2,617

Timestamp

12/10/2013, 2:37:44 AM

Confirmations

6,492,906

Merkle Root

188207e09ff0c5d9efda00645e731bb906fe50684cab87931a667b0ff3266ca4
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.

1.656 × 10⁹⁵(96-digit number)
16565322929596206452…07932508347206689280
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
1.656 × 10⁹⁵(96-digit number)
16565322929596206452…07932508347206689281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
3.313 × 10⁹⁵(96-digit number)
33130645859192412904…15865016694413378561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
6.626 × 10⁹⁵(96-digit number)
66261291718384825809…31730033388826757121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.325 × 10⁹⁶(97-digit number)
13252258343676965161…63460066777653514241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.650 × 10⁹⁶(97-digit number)
26504516687353930323…26920133555307028481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
5.300 × 10⁹⁶(97-digit number)
53009033374707860647…53840267110614056961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.060 × 10⁹⁷(98-digit number)
10601806674941572129…07680534221228113921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.120 × 10⁹⁷(98-digit number)
21203613349883144258…15361068442456227841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
4.240 × 10⁹⁷(98-digit number)
42407226699766288517…30722136884912455681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
8.481 × 10⁹⁷(98-digit number)
84814453399532577035…61444273769824911361
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 302944

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 6ac76aa102c8508481edb67805b6306bd5e9ffbb18fbfcc1ad910b861680e3ff

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 #302,944 on Chainz ↗
Circulating Supply:57,610,885 XPM·at block #6,795,849 · updates every 60s
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