Block #480,936

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 4/8/2014, 2:25:50 PM · Difficulty 10.5254 · 6,325,056 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
f5afcae6b408946bc3f410ad268747fbcc2d0df598f533efd0062810d23db12d

Height

#480,936

Difficulty

10.525404

Transactions

6

Size

1.87 KB

Version

2

Bits

0a8680dc

Nonce

126,732,367

Timestamp

4/8/2014, 2:25:50 PM

Confirmations

6,325,056

Merkle Root

790f461c204d49f0731d2216afaa172ba0e9d1e729910fbfb336c1fbaa4b154c
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.

9.336 × 10⁹⁸(99-digit number)
93364362379754343609…65149980965849308161
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
9.336 × 10⁹⁸(99-digit number)
93364362379754343609…65149980965849308161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.867 × 10⁹⁹(100-digit number)
18672872475950868721…30299961931698616321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
3.734 × 10⁹⁹(100-digit number)
37345744951901737443…60599923863397232641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
7.469 × 10⁹⁹(100-digit number)
74691489903803474887…21199847726794465281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.493 × 10¹⁰⁰(101-digit number)
14938297980760694977…42399695453588930561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.987 × 10¹⁰⁰(101-digit number)
29876595961521389954…84799390907177861121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
5.975 × 10¹⁰⁰(101-digit number)
59753191923042779909…69598781814355722241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.195 × 10¹⁰¹(102-digit number)
11950638384608555981…39197563628711444481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.390 × 10¹⁰¹(102-digit number)
23901276769217111963…78395127257422888961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
4.780 × 10¹⁰¹(102-digit number)
47802553538434223927…56790254514845777921
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:57,692,014 XPM·at block #6,805,991 · updates every 60s
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