Block #342,586

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/4/2014, 4:25:42 AM · Difficulty 10.1570 · 6,465,703 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
0884020913e54384660fb10cb2e5e97ad8b34682557daa8fa6566b450cb7b255

Height

#342,586

Difficulty

10.157004

Transactions

16

Size

5.80 KB

Version

2

Bits

0a283171

Nonce

2,187

Timestamp

1/4/2014, 4:25:42 AM

Confirmations

6,465,703

Merkle Root

db11e17e13f19bfec80924c1711d5c1400c8616794fb06201c2ba65c08fecf53
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.

5.937 × 10⁹⁷(98-digit number)
59377851849299522279…69790288370582794241
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
5.937 × 10⁹⁷(98-digit number)
59377851849299522279…69790288370582794241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.187 × 10⁹⁸(99-digit number)
11875570369859904455…39580576741165588481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.375 × 10⁹⁸(99-digit number)
23751140739719808911…79161153482331176961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
4.750 × 10⁹⁸(99-digit number)
47502281479439617823…58322306964662353921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
9.500 × 10⁹⁸(99-digit number)
95004562958879235647…16644613929324707841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.900 × 10⁹⁹(100-digit number)
19000912591775847129…33289227858649415681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
3.800 × 10⁹⁹(100-digit number)
38001825183551694259…66578455717298831361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
7.600 × 10⁹⁹(100-digit number)
76003650367103388518…33156911434597662721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.520 × 10¹⁰⁰(101-digit number)
15200730073420677703…66313822869195325441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
3.040 × 10¹⁰⁰(101-digit number)
30401460146841355407…32627645738390650881
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:57,710,364 XPM·at block #6,808,288 · updates every 60s
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