Home/Chain Registry/Block #284,934

Block #284,934

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 11/30/2013, 7:41:21 AM · Difficulty 9.9835 · 6,515,650 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
fd275686f3f299e24e4f2a3bd967b625a392adc704ccbeb5c1b2a623dab1058f

Height

#284,934

Difficulty

9.983501

Transactions

5

Size

2.63 KB

Version

2

Bits

09fbc6b2

Nonce

34,132

Timestamp

11/30/2013, 7:41:21 AM

Confirmations

6,515,650

Merkle Root

928bdf31d85287cae3618c39ad0d881a76831f30b2e90e72ca6fd16130edd41a
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.

1.152 × 10⁹⁶(97-digit number)
11523234264981077581…16207707400753356800
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
1.152 × 10⁹⁶(97-digit number)
11523234264981077581…16207707400753356801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.304 × 10⁹⁶(97-digit number)
23046468529962155163…32415414801506713601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
4.609 × 10⁹⁶(97-digit number)
46092937059924310327…64830829603013427201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
9.218 × 10⁹⁶(97-digit number)
92185874119848620654…29661659206026854401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.843 × 10⁹⁷(98-digit number)
18437174823969724130…59323318412053708801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
3.687 × 10⁹⁷(98-digit number)
36874349647939448261…18646636824107417601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
7.374 × 10⁹⁷(98-digit number)
73748699295878896523…37293273648214835201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.474 × 10⁹⁸(99-digit number)
14749739859175779304…74586547296429670401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.949 × 10⁹⁸(99-digit number)
29499479718351558609…49173094592859340801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
5.899 × 10⁹⁸(99-digit number)
58998959436703117218…98346189185718681601
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 284934

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 fd275686f3f299e24e4f2a3bd967b625a392adc704ccbeb5c1b2a623dab1058f

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 #284,934 on Chainz ↗
Circulating Supply:57,648,730 XPM·at block #6,800,583 · updates every 60s
xpmprime.info is a work in progress. If you enjoy using this service you can support this project with a Primecoin donation.