Home/Chain Registry/Block #2,291,619

Block #2,291,619

2CCLength 10ā˜…ā˜…ā˜†ā˜†ā˜†

Cunningham Chain of the Second Kind Ā· Discovered 9/11/2017, 5:12:21 AM Ā· Difficulty 10.9550 Ā· 4,548,498 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
03b57b3a826a9c4b329c7029abb88d7d8e156cb103e2160f26503b556824db80

Difficulty

10.955013

Transactions

4

Size

878 B

Version

2

Bits

0af47bc0

Nonce

26,210,399

Timestamp

9/11/2017, 5:12:21 AM

Confirmations

4,548,498

Merkle Root

f1be87a627a4a5bbf315923695d05271495a4bd18ba1f28bc1d0d37768e1a204
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.

1.382 Ɨ 10⁹⁓(95-digit number)
13821040144940924484…97723424359856052680
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
1.382 Ɨ 10⁹⁓(95-digit number)
13821040144940924484…97723424359856052681
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2āˆ’1 →
2
2^1 Ɨ origin + 1
2.764 Ɨ 10⁹⁓(95-digit number)
27642080289881848968…95446848719712105361
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2āˆ’1 →
3
2^2 Ɨ origin + 1
5.528 Ɨ 10⁹⁓(95-digit number)
55284160579763697936…90893697439424210721
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2āˆ’1 →
4
2^3 Ɨ origin + 1
1.105 Ɨ 10⁹⁵(96-digit number)
11056832115952739587…81787394878848421441
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2āˆ’1 →
5
2^4 Ɨ origin + 1
2.211 Ɨ 10⁹⁵(96-digit number)
22113664231905479174…63574789757696842881
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2āˆ’1 →
6
2^5 Ɨ origin + 1
4.422 Ɨ 10⁹⁵(96-digit number)
44227328463810958349…27149579515393685761
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2āˆ’1 →
7
2^6 Ɨ origin + 1
8.845 Ɨ 10⁹⁵(96-digit number)
88454656927621916698…54299159030787371521
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2āˆ’1 →
8
2^7 Ɨ origin + 1
1.769 Ɨ 10⁹⁶(97-digit number)
17690931385524383339…08598318061574743041
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2āˆ’1 →
9
2^8 Ɨ origin + 1
3.538 Ɨ 10⁹⁶(97-digit number)
35381862771048766679…17196636123149486081
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2āˆ’1 →
10
2^9 Ɨ origin + 1
7.076 Ɨ 10⁹⁶(97-digit number)
70763725542097533359…34393272246298972161
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 2291619

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 03b57b3a826a9c4b329c7029abb88d7d8e156cb103e2160f26503b556824db80

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 #2,291,619 on Chainz ↗
Circulating Supply:57,965,248 XPMĀ·at block #6,840,116 Ā· updates every 60s
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