Block #361,579

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/16/2014, 4:18:42 AM · Difficulty 10.4056 · 6,434,565 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
a5f3000aff845d59f2f72cd8608d8ba6312402b51ccb797450395b2a75367032

Height

#361,579

Difficulty

10.405563

Transactions

5

Size

1.23 KB

Version

2

Bits

0a67d2f8

Nonce

8,576

Timestamp

1/16/2014, 4:18:42 AM

Confirmations

6,434,565

Merkle Root

c4d395a172932b8e2fe83eaea8aa5be72c8d1e7dbbd3db0f04bb5d217283181f
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.

1.853 × 10⁹⁶(97-digit number)
18538726154046022662…00621381532534177501
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
1.853 × 10⁹⁶(97-digit number)
18538726154046022662…00621381532534177501
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
3.707 × 10⁹⁶(97-digit number)
37077452308092045325…01242763065068355001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
7.415 × 10⁹⁶(97-digit number)
74154904616184090650…02485526130136710001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.483 × 10⁹⁷(98-digit number)
14830980923236818130…04971052260273420001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.966 × 10⁹⁷(98-digit number)
29661961846473636260…09942104520546840001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
5.932 × 10⁹⁷(98-digit number)
59323923692947272520…19884209041093680001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.186 × 10⁹⁸(99-digit number)
11864784738589454504…39768418082187360001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.372 × 10⁹⁸(99-digit number)
23729569477178909008…79536836164374720001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
4.745 × 10⁹⁸(99-digit number)
47459138954357818016…59073672328749440001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
9.491 × 10⁹⁸(99-digit number)
94918277908715636032…18147344657498880001
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 Second 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 2CC formula:

2CC: p₁ (first prime), p₂ = 2p₁ − 1, p₃ = 2p₂ − 1, …
Circulating Supply:57,613,149 XPM·at block #6,796,143 · 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.