XPM Prime Explorer symbol
XPMPrime Explorer
Home/Chain Registry/Block #1,279,981

Block #1,279,981

2CCLength 10β˜…β˜…β˜†β˜†β˜†

Cunningham Chain of the Second Kind Β· Discovered 10/13/2015, 9:35:45 AM Β· Difficulty 10.8368 Β· 5,514,788 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
ebd8371d038d5e96ff2fb6df25f1c2524efd7d84fa6537eeffdd42d2e3b15a43
View on Chainz β†—

Difficulty

10.836768

Transactions

1

Size

198 B

Version

2

Bits

0ad63669

Nonce

838,643,613

Timestamp

10/13/2015, 9:35:45 AM

Confirmations

5,514,788

Merkle Root

4461a67efb00da21b34dc8209b30c33c074c258c91bc7860b0029402bb87e85b
Transactions (1)
Coinbase4461a67efb00da…029402bb87e85b
1 in β†’ 1 out8.5000 XPM109 B
APc5cr8z…mzE933mm
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.

2.455 Γ— 10⁹¹(92-digit number)
24550380711171841352…05346559046657988610
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
2.455 Γ— 10⁹¹(92-digit number)
24550380711171841352…05346559046657988611
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
2
2^1 Γ— origin + 1
4.910 Γ— 10⁹¹(92-digit number)
49100761422343682704…10693118093315977221
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
3
2^2 Γ— origin + 1
9.820 Γ— 10⁹¹(92-digit number)
98201522844687365408…21386236186631954441
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
4
2^3 Γ— origin + 1
1.964 Γ— 10⁹²(93-digit number)
19640304568937473081…42772472373263908881
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
5
2^4 Γ— origin + 1
3.928 Γ— 10⁹²(93-digit number)
39280609137874946163…85544944746527817761
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
6
2^5 Γ— origin + 1
7.856 Γ— 10⁹²(93-digit number)
78561218275749892326…71089889493055635521
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
7
2^6 Γ— origin + 1
1.571 Γ— 10⁹³(94-digit number)
15712243655149978465…42179778986111271041
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
8
2^7 Γ— origin + 1
3.142 Γ— 10⁹³(94-digit number)
31424487310299956930…84359557972222542081
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
9
2^8 Γ— origin + 1
6.284 Γ— 10⁹³(94-digit number)
62848974620599913861…68719115944445084161
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
10
2^9 Γ— origin + 1
1.256 Γ— 10⁹⁴(95-digit number)
12569794924119982772…37438231888890168321
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 1279981

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 ebd8371d038d5e96ff2fb6df25f1c2524efd7d84fa6537eeffdd42d2e3b15a43

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 #1,279,981 on Chainz β†—
Circulating Supply:57,602,202 XPMΒ·at block #6,794,768 Β· updates every 60s
xpmprime.info is a work in progress. If you enjoy using this service you can support this project with a Primecoin donation.
AQZeJoQ81VgeHQBpEYTgvNqV1gnz3L5SvK