Block #470,325

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 4/1/2014, 8:01:35 PM · Difficulty 10.4323 · 6,332,237 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
a05f57311b7a99e720904d3b6c40ce9e416fe45840d8bec0c6ee320d7c6061d6

Height

#470,325

Difficulty

10.432304

Transactions

1

Size

1001 B

Version

2

Bits

0a6eab77

Nonce

847,435

Timestamp

4/1/2014, 8:01:35 PM

Confirmations

6,332,237

Merkle Root

95a371ceb2cb3c1cd836b189947cab494184dfadc3f6b5b8920c2d8285a0c020
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.

1.617 × 10⁹²(93-digit number)
16175900287592529881…40938142754246237441
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
1.617 × 10⁹²(93-digit number)
16175900287592529881…40938142754246237441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
3.235 × 10⁹²(93-digit number)
32351800575185059762…81876285508492474881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
6.470 × 10⁹²(93-digit number)
64703601150370119524…63752571016984949761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.294 × 10⁹³(94-digit number)
12940720230074023904…27505142033969899521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.588 × 10⁹³(94-digit number)
25881440460148047809…55010284067939799041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
5.176 × 10⁹³(94-digit number)
51762880920296095619…10020568135879598081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.035 × 10⁹⁴(95-digit number)
10352576184059219123…20041136271759196161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.070 × 10⁹⁴(95-digit number)
20705152368118438247…40082272543518392321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
4.141 × 10⁹⁴(95-digit number)
41410304736236876495…80164545087036784641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
8.282 × 10⁹⁴(95-digit number)
82820609472473752991…60329090174073569281
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:57,664,510 XPM·at block #6,802,561 · updates every 60s
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