Home/Chain Registry/Block #844,027

Block #844,027

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/7/2014, 8:15:41 PM · Difficulty 10.9730 · 5,993,976 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
4b297fcff8a048bcc5a7e07596fa4eb25b79be1c5bcc54d52acad09f8441325c

Height

#844,027

Difficulty

10.972966

Transactions

17

Size

4.36 KB

Version

2

Bits

0af9144a

Nonce

5,618,754

Timestamp

12/7/2014, 8:15:41 PM

Confirmations

5,993,976

Merkle Root

6228546411cdadad9a689555ae9aa206e2c740a5f645b4f6160f1d092468e94c
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.

1.193 × 10⁹⁶(97-digit number)
11937097549240456595…15076970736149011840
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
1.193 × 10⁹⁶(97-digit number)
11937097549240456595…15076970736149011841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.387 × 10⁹⁶(97-digit number)
23874195098480913190…30153941472298023681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
4.774 × 10⁹⁶(97-digit number)
47748390196961826381…60307882944596047361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
9.549 × 10⁹⁶(97-digit number)
95496780393923652762…20615765889192094721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.909 × 10⁹⁷(98-digit number)
19099356078784730552…41231531778384189441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
3.819 × 10⁹⁷(98-digit number)
38198712157569461105…82463063556768378881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
7.639 × 10⁹⁷(98-digit number)
76397424315138922210…64926127113536757761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.527 × 10⁹⁸(99-digit number)
15279484863027784442…29852254227073515521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
3.055 × 10⁹⁸(99-digit number)
30558969726055568884…59704508454147031041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
6.111 × 10⁹⁸(99-digit number)
61117939452111137768…19409016908294062081
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 844027

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 4b297fcff8a048bcc5a7e07596fa4eb25b79be1c5bcc54d52acad09f8441325c

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 #844,027 on Chainz ↗
Circulating Supply:57,948,376 XPM·at block #6,838,002 · updates every 60s
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