Block #2,467,731

1CCLength 10★★☆☆☆

Cunningham Chain of the First Kind · Discovered 1/11/2018, 7:33:01 AM · Difficulty 10.9603 · 4,374,366 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
b98d251370ff2c2fbf58e97a76922e6e807ce34014fdb1503f2ad361b9dc0498

Height

#2,467,731

Difficulty

10.960330

Transactions

6

Size

3.83 KB

Version

2

Bits

0af5d829

Nonce

532,384,987

Timestamp

1/11/2018, 7:33:01 AM

Confirmations

4,374,366

Merkle Root

a162f3a24422c4ad221c5ffc9f7b9d666f0ed87df96865e33cabd4066e763587
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.

1.317 × 10⁹⁶(97-digit number)
13176850323737714768…41067404657640449279
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
1.317 × 10⁹⁶(97-digit number)
13176850323737714768…41067404657640449279
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
2.635 × 10⁹⁶(97-digit number)
26353700647475429537…82134809315280898559
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
5.270 × 10⁹⁶(97-digit number)
52707401294950859074…64269618630561797119
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
1.054 × 10⁹⁷(98-digit number)
10541480258990171814…28539237261123594239
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
2.108 × 10⁹⁷(98-digit number)
21082960517980343629…57078474522247188479
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
4.216 × 10⁹⁷(98-digit number)
42165921035960687259…14156949044494376959
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
8.433 × 10⁹⁷(98-digit number)
84331842071921374519…28313898088988753919
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
1.686 × 10⁹⁸(99-digit number)
16866368414384274903…56627796177977507839
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
3.373 × 10⁹⁸(99-digit number)
33732736828768549807…13255592355955015679
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
6.746 × 10⁹⁸(99-digit number)
67465473657537099615…26511184711910031359
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:57,981,162 XPM·at block #6,842,096 · updates every 60s
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