Block #464,347

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 3/28/2014, 5:47:03 PM · Difficulty 10.4195 · 6,351,604 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
a9d306334d105d80601977c90c33ed3d5ecdfda90f5b84fd54be3a9e9c26ec9f

Height

#464,347

Difficulty

10.419507

Transactions

9

Size

2.86 KB

Version

2

Bits

0a6b64cd

Nonce

47,041

Timestamp

3/28/2014, 5:47:03 PM

Confirmations

6,351,604

Merkle Root

96281927403210f8ba5f37b529d10f192c47d9efc4140f484ed2ee670c1362e9
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.

4.946 × 10¹⁰⁰(101-digit number)
49467158843303942228…35871503728366300161
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
4.946 × 10¹⁰⁰(101-digit number)
49467158843303942228…35871503728366300161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
9.893 × 10¹⁰⁰(101-digit number)
98934317686607884456…71743007456732600321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.978 × 10¹⁰¹(102-digit number)
19786863537321576891…43486014913465200641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
3.957 × 10¹⁰¹(102-digit number)
39573727074643153782…86972029826930401281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
7.914 × 10¹⁰¹(102-digit number)
79147454149286307565…73944059653860802561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.582 × 10¹⁰²(103-digit number)
15829490829857261513…47888119307721605121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
3.165 × 10¹⁰²(103-digit number)
31658981659714523026…95776238615443210241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
6.331 × 10¹⁰²(103-digit number)
63317963319429046052…91552477230886420481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.266 × 10¹⁰³(104-digit number)
12663592663885809210…83104954461772840961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.532 × 10¹⁰³(104-digit number)
25327185327771618420…66209908923545681921
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:57,771,723 XPM·at block #6,815,950 · updates every 60s
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