Block #679,578

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 8/16/2014, 1:45:57 AM · Difficulty 10.9631 · 6,129,762 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
29688f9f696fec6d1fb465798e008b7a24d2103c2304c903df55a98315671668

Height

#679,578

Difficulty

10.963107

Transactions

10

Size

2.48 KB

Version

2

Bits

0af68e29

Nonce

467,216,029

Timestamp

8/16/2014, 1:45:57 AM

Confirmations

6,129,762

Merkle Root

ba2e8dabafdace45e2d28c5d94083d993ee25345c7bbe1cf74aaa4477016f144
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.

2.274 × 10⁹⁷(98-digit number)
22740169786503077144…82622055547832704001
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
2.274 × 10⁹⁷(98-digit number)
22740169786503077144…82622055547832704001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
4.548 × 10⁹⁷(98-digit number)
45480339573006154289…65244111095665408001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
9.096 × 10⁹⁷(98-digit number)
90960679146012308579…30488222191330816001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.819 × 10⁹⁸(99-digit number)
18192135829202461715…60976444382661632001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
3.638 × 10⁹⁸(99-digit number)
36384271658404923431…21952888765323264001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
7.276 × 10⁹⁸(99-digit number)
72768543316809846863…43905777530646528001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.455 × 10⁹⁹(100-digit number)
14553708663361969372…87811555061293056001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.910 × 10⁹⁹(100-digit number)
29107417326723938745…75623110122586112001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
5.821 × 10⁹⁹(100-digit number)
58214834653447877491…51246220245172224001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.164 × 10¹⁰⁰(101-digit number)
11642966930689575498…02492440490344448001
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:57,718,785 XPM·at block #6,809,339 · updates every 60s
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