Block #346,723

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/6/2014, 5:44:39 PM · Difficulty 10.2313 · 6,463,798 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
a6140420348a69ecec8043deebe9aec89edb37f86f6cbce3ee22c5f8132e2619

Height

#346,723

Difficulty

10.231281

Transactions

1

Size

1.01 KB

Version

2

Bits

0a3b353c

Nonce

2,795

Timestamp

1/6/2014, 5:44:39 PM

Confirmations

6,463,798

Merkle Root

2432abcf204742473c4eadcaa0d394cc5af45e6c56e78efcb91e69f4e471346c
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.

3.234 × 10⁹⁶(97-digit number)
32342353640771646041…45822445918015413761
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
3.234 × 10⁹⁶(97-digit number)
32342353640771646041…45822445918015413761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
6.468 × 10⁹⁶(97-digit number)
64684707281543292083…91644891836030827521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.293 × 10⁹⁷(98-digit number)
12936941456308658416…83289783672061655041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.587 × 10⁹⁷(98-digit number)
25873882912617316833…66579567344123310081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
5.174 × 10⁹⁷(98-digit number)
51747765825234633666…33159134688246620161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.034 × 10⁹⁸(99-digit number)
10349553165046926733…66318269376493240321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.069 × 10⁹⁸(99-digit number)
20699106330093853466…32636538752986480641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
4.139 × 10⁹⁸(99-digit number)
41398212660187706933…65273077505972961281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
8.279 × 10⁹⁸(99-digit number)
82796425320375413867…30546155011945922561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.655 × 10⁹⁹(100-digit number)
16559285064075082773…61092310023891845121
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:57,728,254 XPM·at block #6,810,520 · updates every 60s
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