Block #376,126

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/26/2014, 4:56:17 AM · Difficulty 10.4232 · 6,434,654 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
b4b180e3a37b7441be1c98853f9e8b8763994f23ecc69bb6158c25d1789682e5

Height

#376,126

Difficulty

10.423182

Transactions

3

Size

1.59 KB

Version

2

Bits

0a6c55aa

Nonce

47,954

Timestamp

1/26/2014, 4:56:17 AM

Confirmations

6,434,654

Merkle Root

753d97217d957f01f29a264e8720611227edd7c61c696ebf16a2c2b0591ca801
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.

1.059 × 10⁹⁸(99-digit number)
10598206505960592785…10613655280646801151
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
1.059 × 10⁹⁸(99-digit number)
10598206505960592785…10613655280646801151
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.119 × 10⁹⁸(99-digit number)
21196413011921185570…21227310561293602301
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
4.239 × 10⁹⁸(99-digit number)
42392826023842371141…42454621122587204601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
8.478 × 10⁹⁸(99-digit number)
84785652047684742282…84909242245174409201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.695 × 10⁹⁹(100-digit number)
16957130409536948456…69818484490348818401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
3.391 × 10⁹⁹(100-digit number)
33914260819073896913…39636968980697636801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
6.782 × 10⁹⁹(100-digit number)
67828521638147793826…79273937961395273601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.356 × 10¹⁰⁰(101-digit number)
13565704327629558765…58547875922790547201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.713 × 10¹⁰⁰(101-digit number)
27131408655259117530…17095751845581094401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
5.426 × 10¹⁰⁰(101-digit number)
54262817310518235060…34191503691162188801
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:57,730,337 XPM·at block #6,810,779 · updates every 60s
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