Block #1,541,482

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 4/14/2016, 9:04:09 PM · Difficulty 10.6452 · 5,285,628 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
81ee0db9f7558c1eca97003fe959fe84dd3ef09c30fad4288b87e3dea6641d89

Height

#1,541,482

Difficulty

10.645248

Transactions

2

Size

1.08 KB

Version

2

Bits

0aa52ef8

Nonce

203,541,963

Timestamp

4/14/2016, 9:04:09 PM

Confirmations

5,285,628

Merkle Root

015be90a4c5a59099c1b064fd044a2effb868845fe60d3e13fc6e4c3541cc8cf
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.

2.334 × 10⁹⁴(95-digit number)
23347832605750873371…54044504664736230481
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
2.334 × 10⁹⁴(95-digit number)
23347832605750873371…54044504664736230481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
4.669 × 10⁹⁴(95-digit number)
46695665211501746742…08089009329472460961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
9.339 × 10⁹⁴(95-digit number)
93391330423003493484…16178018658944921921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.867 × 10⁹⁵(96-digit number)
18678266084600698696…32356037317889843841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
3.735 × 10⁹⁵(96-digit number)
37356532169201397393…64712074635779687681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
7.471 × 10⁹⁵(96-digit number)
74713064338402794787…29424149271559375361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.494 × 10⁹⁶(97-digit number)
14942612867680558957…58848298543118750721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.988 × 10⁹⁶(97-digit number)
29885225735361117914…17696597086237501441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
5.977 × 10⁹⁶(97-digit number)
59770451470722235829…35393194172475002881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.195 × 10⁹⁷(98-digit number)
11954090294144447165…70786388344950005761
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:57,861,059 XPM·at block #6,827,109 · updates every 60s
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