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Home/Chain Registry/Block #913,120

Block #913,120

2CCLength 10β˜…β˜…β˜†β˜†β˜†

Cunningham Chain of the Second Kind Β· Discovered 1/28/2015, 10:51:59 AM Β· Difficulty 10.9277 Β· 5,882,317 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
d2fa2e9dd81d313627013ff2500ea20e8aade3063bca17f56314d8fc6cdeded4
View on Chainz β†—

Height

#913,120

Difficulty

10.927665

Transactions

2

Size

877 B

Version

2

Bits

0aed7b74

Nonce

551,274,202

Timestamp

1/28/2015, 10:51:59 AM

Confirmations

5,882,317

Merkle Root

d8fa06263a03480bebab9af94b1c2ca2263e480db33dbe3c7c4c4b8848542ac4
Transactions (2)
Coinbase96b4bd32df8609…01790aba040829
1 in β†’ 1 out8.3700 XPM116 B
ANSXnLY2…Sd25TjkD
b0b8f8e59dc4db…613bdd5e7e6da4
4 in β†’ 2 out3726.0000 XPM670 B
Aa43zDeY…p1yP2YvzAG6g15Lu…okSG4T9k
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.

9.037 Γ— 10⁹⁡(96-digit number)
90379342228275382425…15156109200008713120
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
9.037 Γ— 10⁹⁡(96-digit number)
90379342228275382425…15156109200008713121
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
2
2^1 Γ— origin + 1
1.807 Γ— 10⁹⁢(97-digit number)
18075868445655076485…30312218400017426241
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
3
2^2 Γ— origin + 1
3.615 Γ— 10⁹⁢(97-digit number)
36151736891310152970…60624436800034852481
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
4
2^3 Γ— origin + 1
7.230 Γ— 10⁹⁢(97-digit number)
72303473782620305940…21248873600069704961
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
5
2^4 Γ— origin + 1
1.446 Γ— 10⁹⁷(98-digit number)
14460694756524061188…42497747200139409921
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
6
2^5 Γ— origin + 1
2.892 Γ— 10⁹⁷(98-digit number)
28921389513048122376…84995494400278819841
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
7
2^6 Γ— origin + 1
5.784 Γ— 10⁹⁷(98-digit number)
57842779026096244752…69990988800557639681
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
8
2^7 Γ— origin + 1
1.156 Γ— 10⁹⁸(99-digit number)
11568555805219248950…39981977601115279361
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
9
2^8 Γ— origin + 1
2.313 Γ— 10⁹⁸(99-digit number)
23137111610438497901…79963955202230558721
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
10
2^9 Γ— origin + 1
4.627 Γ— 10⁹⁸(99-digit number)
46274223220876995802…59927910404461117441
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 913120

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 d2fa2e9dd81d313627013ff2500ea20e8aade3063bca17f56314d8fc6cdeded4

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 #913,120 on Chainz β†—
Circulating Supply:57,607,559 XPMΒ·at block #6,795,436 Β· updates every 60s
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