XPM Prime Explorer symbol
XPMPrime Explorer

Block #1,092,767

2CCLength 10β˜…β˜…β˜†β˜†β˜†

Cunningham Chain of the Second Kind Β· Discovered 6/6/2015, 8:06:02 PM Β· Difficulty 10.7398 Β· 5,715,416 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
2e763f257dd33cdd226c2cd9da72f4c1be644755adf9b97fb5313f66088b27ac
View on Chainz β†—

Height

#1,092,767

Difficulty

10.739776

Transactions

2

Size

2.98 KB

Version

2

Bits

0abd61f6

Nonce

515,113,081

Timestamp

6/6/2015, 8:06:02 PM

Confirmations

5,715,416

Mined by

⛏️ P2SHAJCEY9yyy2DERzsA24UUtHTMGPtg97E6zm

Merkle Root

b025a252ee78ee412a68c638b177e6c0227ca285d20711de1e126642f06fdaa6
Transactions (2)
Coinbasea20ba99dc5a34f…0dcde4fb0ae4e2
1 in β†’ 1 out8.6900 XPM116 B
AJCEY9yy…tg97E6zm
2deb7ba511f1c3…12cfd6b5e71c5b
19 in β†’ 1 out2.4521 XPM2.78 KB
AVCvdXNe…rAiDsdP4
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.

1.196 Γ— 10⁹⁷(98-digit number)
11969324794437226505…86095442934578586881
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
1.196 Γ— 10⁹⁷(98-digit number)
11969324794437226505…86095442934578586881
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
2
2^1 Γ— origin + 1
2.393 Γ— 10⁹⁷(98-digit number)
23938649588874453011…72190885869157173761
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
3
2^2 Γ— origin + 1
4.787 Γ— 10⁹⁷(98-digit number)
47877299177748906022…44381771738314347521
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
4
2^3 Γ— origin + 1
9.575 Γ— 10⁹⁷(98-digit number)
95754598355497812045…88763543476628695041
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
5
2^4 Γ— origin + 1
1.915 Γ— 10⁹⁸(99-digit number)
19150919671099562409…77527086953257390081
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
6
2^5 Γ— origin + 1
3.830 Γ— 10⁹⁸(99-digit number)
38301839342199124818…55054173906514780161
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
7
2^6 Γ— origin + 1
7.660 Γ— 10⁹⁸(99-digit number)
76603678684398249636…10108347813029560321
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
8
2^7 Γ— origin + 1
1.532 Γ— 10⁹⁹(100-digit number)
15320735736879649927…20216695626059120641
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
9
2^8 Γ— origin + 1
3.064 Γ— 10⁹⁹(100-digit number)
30641471473759299854…40433391252118241281
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
10
2^9 Γ— origin + 1
6.128 Γ— 10⁹⁹(100-digit number)
61282942947518599709…80866782504236482561
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.

β˜…β˜…β˜†β˜†β˜†
Rarity
UncommonChain length 10

Roughly 1 in 100 blocks. Solid but expected in a healthy network.

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, …
Cross-reference on Chainz Explorer
Circulating Supply:57,709,513 XPMΒ·at block #6,808,182 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

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