Home/Chain Registry/Block #2,202,170

Block #2,202,170

2CCLength 10ā˜…ā˜…ā˜†ā˜†ā˜†

Cunningham Chain of the Second Kind Ā· Discovered 7/11/2017, 8:04:46 AM Ā· Difficulty 10.9492 Ā· 4,643,167 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
6060e1e9a0331cd91a1d686a766762f8197dcb90b49082ec887e5f7e64fb2930

Difficulty

10.949191

Transactions

4

Size

2.41 KB

Version

2

Bits

0af2fe2a

Nonce

557,632,174

Timestamp

7/11/2017, 8:04:46 AM

Confirmations

4,643,167

Merkle Root

d9478aaa63575eb833c28a1182eee475d9231b2fd292ae9fa0a16c918bab9dda
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.

2.351 Ɨ 10⁹⁵(96-digit number)
23511381063145070066…83554803843492220840
Discovered Prime Numbers
p_k = 2^k Ɨ 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
2.351 Ɨ 10⁹⁵(96-digit number)
23511381063145070066…83554803843492220841
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2āˆ’1 →
2
2^1 Ɨ origin + 1
4.702 Ɨ 10⁹⁵(96-digit number)
47022762126290140132…67109607686984441681
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2āˆ’1 →
3
2^2 Ɨ origin + 1
9.404 Ɨ 10⁹⁵(96-digit number)
94045524252580280264…34219215373968883361
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2āˆ’1 →
4
2^3 Ɨ origin + 1
1.880 Ɨ 10⁹⁶(97-digit number)
18809104850516056052…68438430747937766721
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2āˆ’1 →
5
2^4 Ɨ origin + 1
3.761 Ɨ 10⁹⁶(97-digit number)
37618209701032112105…36876861495875533441
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2āˆ’1 →
6
2^5 Ɨ origin + 1
7.523 Ɨ 10⁹⁶(97-digit number)
75236419402064224211…73753722991751066881
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2āˆ’1 →
7
2^6 Ɨ origin + 1
1.504 Ɨ 10⁹⁷(98-digit number)
15047283880412844842…47507445983502133761
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2āˆ’1 →
8
2^7 Ɨ origin + 1
3.009 Ɨ 10⁹⁷(98-digit number)
30094567760825689684…95014891967004267521
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2āˆ’1 →
9
2^8 Ɨ origin + 1
6.018 Ɨ 10⁹⁷(98-digit number)
60189135521651379369…90029783934008535041
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2āˆ’1 →
10
2^9 Ɨ origin + 1
1.203 Ɨ 10⁹⁸(99-digit number)
12037827104330275873…80059567868017070081
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 →
ā˜…ā˜…ā˜†ā˜†ā˜†
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 Ɨ 3 Ɨ 5 Ɨ 7 Ɨ …), 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 Ɨ Primorial (2Ā·3Ā·5Ā·7Ā·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), pā‚‚ = 2p₁ āˆ’ 1, pā‚ƒ = 2pā‚‚ āˆ’ 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 2202170

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 6060e1e9a0331cd91a1d686a766762f8197dcb90b49082ec887e5f7e64fb2930

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 #2,202,170 on Chainz ↗
Circulating Supply:58,007,138 XPMĀ·at block #6,845,336 Ā· updates every 60s
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