Home/Chain Registry/Block #347,808

Block #347,808

2CCLength 10β˜…β˜…β˜†β˜†β˜†

Cunningham Chain of the Second Kind Β· Discovered 1/7/2014, 10:47:13 AM Β· Difficulty 10.2408 Β· 6,466,309 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
82b89b40a2fc076a1d72a23ca808f492149c28828b5abcb69862eef998969005

Height

#347,808

Difficulty

10.240812

Transactions

1

Size

206 B

Version

2

Bits

0a3da5e3

Nonce

148,445

Timestamp

1/7/2014, 10:47:13 AM

Confirmations

6,466,309

Merkle Root

3b82b0846d83f549714efbe5c4fa4ef64192c0dddbc9b94e217fe903833b636b
Transactions (1)
1 in β†’ 1 out9.5200 XPM116 B
Prime Chain Origin

This is the prime chain origin stored in the block header. It is a composite number (not prime itself) β€” it equals the first prime in the chain multiplied by a primorial. The origin anchors the entire chain to this specific block.

2.908 Γ— 10⁹⁡(96-digit number)
29084417538912988015…93761103574211763200
Discovered Prime Numbers
p_k = 2^k Γ— 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
2.908 Γ— 10⁹⁡(96-digit number)
29084417538912988015…93761103574211763201
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
2
2^1 Γ— origin + 1
5.816 Γ— 10⁹⁡(96-digit number)
58168835077825976031…87522207148423526401
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
3
2^2 Γ— origin + 1
1.163 Γ— 10⁹⁢(97-digit number)
11633767015565195206…75044414296847052801
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
4
2^3 Γ— origin + 1
2.326 Γ— 10⁹⁢(97-digit number)
23267534031130390412…50088828593694105601
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
5
2^4 Γ— origin + 1
4.653 Γ— 10⁹⁢(97-digit number)
46535068062260780825…00177657187388211201
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
6
2^5 Γ— origin + 1
9.307 Γ— 10⁹⁢(97-digit number)
93070136124521561650…00355314374776422401
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
7
2^6 Γ— origin + 1
1.861 Γ— 10⁹⁷(98-digit number)
18614027224904312330…00710628749552844801
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
8
2^7 Γ— origin + 1
3.722 Γ— 10⁹⁷(98-digit number)
37228054449808624660…01421257499105689601
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
9
2^8 Γ— origin + 1
7.445 Γ— 10⁹⁷(98-digit number)
74456108899617249320…02842514998211379201
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
10
2^9 Γ— origin + 1
1.489 Γ— 10⁹⁸(99-digit number)
14891221779923449864…05685029996422758401
Verify on FactorDB β†—Wolfram Alpha β†—

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 β€” the large number shown above β€” 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 β†’
β˜…β˜…β˜†β˜†β˜†
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 Γ— 3 Γ— 5 Γ— 7 Γ— …), the result is the first prime in the chain. The origin is deliberately divisible by this primorial β€” that divisibility is part of the proof.

Prime Chain Origin = First Prime Γ— Primorial (2Β·3Β·5Β·7Β·11·…)
Source: Primecoin prime.cpp β€” CheckPrimeProofOfWork()

This is why the origin has many small prime factors β€” those factors are the primorial divisor. The chain then extends from the first prime using the 2CC formula:

2CC: p₁ (first prime), pβ‚‚ = 2p₁ βˆ’ 1, p₃ = 2pβ‚‚ βˆ’ 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 347808

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 82b89b40a2fc076a1d72a23ca808f492149c28828b5abcb69862eef998969005

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 β†’ Debug Window β†’ 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 #347,808 on Chainz β†—
Circulating Supply:57,757,019 XPMΒ·at block #6,814,116 Β· updates every 60s
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