XPM Prime Explorer symbol
XPMPrime Explorer
Home/Chain Registry/Block #1,976,604

Block #1,976,604

2CCLength 10β˜…β˜…β˜†β˜†β˜†

Cunningham Chain of the Second Kind Β· Discovered 2/9/2017, 9:50:54 PM Β· Difficulty 10.7585 Β· 4,860,867 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
c0c8f019600a28abb1e3139104f26ca4117076411f5bfd0a9edbf1e3bb7028c2
View on Chainz β†—

Difficulty

10.758468

Transactions

1

Size

200 B

Version

2

Bits

0ac22af7

Nonce

348,375,273

Timestamp

2/9/2017, 9:50:54 PM

Confirmations

4,860,867

Merkle Root

739e18c735972afd11e12bff833c70f8d3df0e3251de2013f6a82b761927ea97
Transactions (1)
Coinbase739e18c735972a…a82b761927ea97
1 in β†’ 1 out8.6300 XPM109 B
ASaqtNqp…KqybRxuC
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.

1.192 Γ— 10⁹⁷(98-digit number)
11925470975080473046…83367208294916464640
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
1.192 Γ— 10⁹⁷(98-digit number)
11925470975080473046…83367208294916464641
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
2
2^1 Γ— origin + 1
2.385 Γ— 10⁹⁷(98-digit number)
23850941950160946093…66734416589832929281
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
3
2^2 Γ— origin + 1
4.770 Γ— 10⁹⁷(98-digit number)
47701883900321892186…33468833179665858561
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
4
2^3 Γ— origin + 1
9.540 Γ— 10⁹⁷(98-digit number)
95403767800643784372…66937666359331717121
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
5
2^4 Γ— origin + 1
1.908 Γ— 10⁹⁸(99-digit number)
19080753560128756874…33875332718663434241
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
6
2^5 Γ— origin + 1
3.816 Γ— 10⁹⁸(99-digit number)
38161507120257513748…67750665437326868481
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
7
2^6 Γ— origin + 1
7.632 Γ— 10⁹⁸(99-digit number)
76323014240515027497…35501330874653736961
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
8
2^7 Γ— origin + 1
1.526 Γ— 10⁹⁹(100-digit number)
15264602848103005499…71002661749307473921
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
9
2^8 Γ— origin + 1
3.052 Γ— 10⁹⁹(100-digit number)
30529205696206010999…42005323498614947841
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
10
2^9 Γ— origin + 1
6.105 Γ— 10⁹⁹(100-digit number)
61058411392412021998…84010646997229895681
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 1976604

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 c0c8f019600a28abb1e3139104f26ca4117076411f5bfd0a9edbf1e3bb7028c2

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 #1,976,604 on Chainz β†—
Circulating Supply:57,944,088 XPMΒ·at block #6,837,470 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.
Privacy PolicyΒ·
AQZeJoQ81VgeHQBpEYTgvNqV1gnz3L5SvK

Cookie Preferences

We use cookies to enhance your experience. Some are essential for the site to function, while others help us understand how you use the site.

Β·Privacy Policy