Block #150,324

2CCLength 9★☆☆☆☆

Cunningham Chain of the Second Kind · Discovered 9/4/2013, 10:54:31 PM · Difficulty 9.8590 · 6,658,564 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
28dbaf742c0dcb0858f6db1880c4a0c0628219d59efa1721bed38b5054f9f239

Height

#150,324

Difficulty

9.858980

Transactions

15

Size

5.13 KB

Version

2

Bits

09dbe623

Nonce

43,368

Timestamp

9/4/2013, 10:54:31 PM

Confirmations

6,658,564

Merkle Root

ed0a598f7a42530ab21b751573961096b336701c9e3c7bf534a80fc041894c74
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.

1.776 × 10⁹²(93-digit number)
17761726595230550501…29815686984382998401
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
1.776 × 10⁹²(93-digit number)
17761726595230550501…29815686984382998401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
3.552 × 10⁹²(93-digit number)
35523453190461101002…59631373968765996801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
7.104 × 10⁹²(93-digit number)
71046906380922202005…19262747937531993601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.420 × 10⁹³(94-digit number)
14209381276184440401…38525495875063987201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.841 × 10⁹³(94-digit number)
28418762552368880802…77050991750127974401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
5.683 × 10⁹³(94-digit number)
56837525104737761604…54101983500255948801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.136 × 10⁹⁴(95-digit number)
11367505020947552320…08203967000511897601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.273 × 10⁹⁴(95-digit number)
22735010041895104641…16407934001023795201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
4.547 × 10⁹⁴(95-digit number)
45470020083790209283…32815868002047590401
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 9 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
CommonChain length 9

Found in most blocks. The baseline for Primecoin's proof-of-work.

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:57,715,155 XPM·at block #6,808,887 · updates every 60s
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