Block #431,038

1CCLength 10★★☆☆☆

Cunningham Chain of the First Kind · Discovered 3/5/2014, 10:00:01 PM · Difficulty 10.3454 · 6,371,744 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
655a247be850d0adaa20e9d97d9eede38d04ef2c287e11f7a9d1560da6d723e3

Height

#431,038

Difficulty

10.345447

Transactions

4

Size

1.44 KB

Version

2

Bits

0a586f38

Nonce

19,459

Timestamp

3/5/2014, 10:00:01 PM

Confirmations

6,371,744

Merkle Root

c1c2b5f929499d2ca53dae918f5203a75fb9595cb5cca88928cea8fe33ec304a
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.

2.071 × 10⁹⁹(100-digit number)
20717913353400516738…58521185856746540639
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
2.071 × 10⁹⁹(100-digit number)
20717913353400516738…58521185856746540639
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
4.143 × 10⁹⁹(100-digit number)
41435826706801033476…17042371713493081279
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
8.287 × 10⁹⁹(100-digit number)
82871653413602066953…34084743426986162559
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
1.657 × 10¹⁰⁰(101-digit number)
16574330682720413390…68169486853972325119
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
3.314 × 10¹⁰⁰(101-digit number)
33148661365440826781…36338973707944650239
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
6.629 × 10¹⁰⁰(101-digit number)
66297322730881653563…72677947415889300479
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
1.325 × 10¹⁰¹(102-digit number)
13259464546176330712…45355894831778600959
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
2.651 × 10¹⁰¹(102-digit number)
26518929092352661425…90711789663557201919
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
5.303 × 10¹⁰¹(102-digit number)
53037858184705322850…81423579327114403839
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
1.060 × 10¹⁰²(103-digit number)
10607571636941064570…62847158654228807679
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 First 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 1CC formula:

1CC: p₁ (first prime), p₂ = 2p₁ + 1, p₃ = 2p₂ + 1, …
Circulating Supply:57,666,280 XPM·at block #6,802,781 · 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.