Block #328,066

1CCLength 10★★☆☆☆

Cunningham Chain of the First Kind · Discovered 12/25/2013, 12:16:14 AM · Difficulty 10.1732 · 6,473,747 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
d7ef2188dbaf99e6f3da6891ff27e934a3bf7528518c944848d1b30e3e7a37d0

Height

#328,066

Difficulty

10.173242

Transactions

13

Size

4.27 KB

Version

2

Bits

0a2c5993

Nonce

82,894

Timestamp

12/25/2013, 12:16:14 AM

Confirmations

6,473,747

Merkle Root

c2c8122d58a03fe6201a4473b33d051c15e0cc4cf3157c4d262c237495ad74c5
Prime Chain Origin

This is the prime chain origin stored in the block header. It is a composite number (not prime itself) — it equals the first prime in the chain multiplied by a primorial. The origin anchors the entire chain to this specific block.

9.484 × 10⁹⁵(96-digit number)
94845638470439524207…09210385702619463679
Discovered Prime Numbers
p_k = 2^k × 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
9.484 × 10⁹⁵(96-digit number)
94845638470439524207…09210385702619463679
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
1.896 × 10⁹⁶(97-digit number)
18969127694087904841…18420771405238927359
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
3.793 × 10⁹⁶(97-digit number)
37938255388175809682…36841542810477854719
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
7.587 × 10⁹⁶(97-digit number)
75876510776351619365…73683085620955709439
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
1.517 × 10⁹⁷(98-digit number)
15175302155270323873…47366171241911418879
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
3.035 × 10⁹⁷(98-digit number)
30350604310540647746…94732342483822837759
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
6.070 × 10⁹⁷(98-digit number)
60701208621081295492…89464684967645675519
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
1.214 × 10⁹⁸(99-digit number)
12140241724216259098…78929369935291351039
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
2.428 × 10⁹⁸(99-digit number)
24280483448432518197…57858739870582702079
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
4.856 × 10⁹⁸(99-digit number)
48560966896865036394…15717479741165404159
Verify on FactorDB ↗Wolfram Alpha ↗

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 — the large number shown above — anchors the chain and is divisible by a primorial (the product of small primes), cryptographically tying these prime numbers to this specific block.

★★☆☆☆
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 × 3 × 5 × 7 × …), the result is the first prime in the chain. The origin is deliberately divisible by this primorial — that divisibility is part of the proof.

Prime Chain Origin = First Prime × Primorial (2·3·5·7·11·…)
Source: Primecoin prime.cpp — CheckPrimeProofOfWork()

This is why the origin has many small prime factors — those factors are the primorial divisor. The chain then extends from the first prime using the 1CC formula:

1CC: p₁ (first prime), p₂ = 2p₁ + 1, p₃ = 2p₂ + 1, …
Circulating Supply:57,658,596 XPM·at block #6,801,812 · 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.