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Home/Chain Registry/Block #1,680,928

Block #1,680,928

1CCLength 10β˜…β˜…β˜†β˜†β˜†

Cunningham Chain of the First Kind Β· Discovered 7/20/2016, 1:15:07 AM Β· Difficulty 10.7116 Β· 5,149,686 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
ea2a620006f2c83a2c76ac29cbb37b7aa689033635723196e91fd7e09c19db2e
View on Chainz β†—

Difficulty

10.711560

Transactions

1

Size

242 B

Version

2

Bits

0ab628c5

Nonce

3,483,086

Timestamp

7/20/2016, 1:15:07 AM

Confirmations

5,149,686

Merkle Root

7e8c27762db458f9aa9a1d750e5b354036353a9ce0aa59cfb4a9700016dcd396
Transactions (1)
Coinbase7e8c27762db458…a9700016dcd396
1 in β†’ 2 out8.7000 XPM152 B
AW7XpJLz…npEJgCfvALPu3s2c…EJXLjVFh
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.

1.942 Γ— 10⁹⁡(96-digit number)
19423136328473997838…62467403639332384000
Discovered Prime Numbers
p_k = 2^k Γ— origin βˆ’ 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 βˆ’ 1
1.942 Γ— 10⁹⁡(96-digit number)
19423136328473997838…62467403639332383999
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
2
2^1 Γ— origin βˆ’ 1
3.884 Γ— 10⁹⁡(96-digit number)
38846272656947995676…24934807278664767999
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
3
2^2 Γ— origin βˆ’ 1
7.769 Γ— 10⁹⁡(96-digit number)
77692545313895991352…49869614557329535999
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
4
2^3 Γ— origin βˆ’ 1
1.553 Γ— 10⁹⁢(97-digit number)
15538509062779198270…99739229114659071999
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
5
2^4 Γ— origin βˆ’ 1
3.107 Γ— 10⁹⁢(97-digit number)
31077018125558396541…99478458229318143999
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
6
2^5 Γ— origin βˆ’ 1
6.215 Γ— 10⁹⁢(97-digit number)
62154036251116793082…98956916458636287999
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
7
2^6 Γ— origin βˆ’ 1
1.243 Γ— 10⁹⁷(98-digit number)
12430807250223358616…97913832917272575999
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
8
2^7 Γ— origin βˆ’ 1
2.486 Γ— 10⁹⁷(98-digit number)
24861614500446717232…95827665834545151999
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
9
2^8 Γ— origin βˆ’ 1
4.972 Γ— 10⁹⁷(98-digit number)
49723229000893434465…91655331669090303999
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
10
2^9 Γ— origin βˆ’ 1
9.944 Γ— 10⁹⁷(98-digit number)
99446458001786868931…83310663338180607999
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 First 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 1CC formula:

1CC: p₁ (first prime), pβ‚‚ = 2p₁ + 1, p₃ = 2pβ‚‚ + 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 1680928

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 ea2a620006f2c83a2c76ac29cbb37b7aa689033635723196e91fd7e09c19db2e

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 #1,680,928 on Chainz β†—
Circulating Supply:57,889,036 XPMΒ·at block #6,830,613 Β· updates every 60s
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