Block #352,467

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/10/2014, 8:45:50 AM · Difficulty 10.3084 · 6,453,385 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
49b2d22d0ae4dbbb5bebb9495945ad5e91c79560e105f99b99cb92665cb7ed14

Height

#352,467

Difficulty

10.308371

Transactions

4

Size

1.74 KB

Version

2

Bits

0a4ef167

Nonce

11,169

Timestamp

1/10/2014, 8:45:50 AM

Confirmations

6,453,385

Merkle Root

8a90cbf3dac18a7f3e161c25cfb037fd91b072435ea0580d5af35e484cb7a99b
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.

3.960 × 10⁹³(94-digit number)
39601130182306518639…87647904291846932481
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
3.960 × 10⁹³(94-digit number)
39601130182306518639…87647904291846932481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
7.920 × 10⁹³(94-digit number)
79202260364613037279…75295808583693864961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.584 × 10⁹⁴(95-digit number)
15840452072922607455…50591617167387729921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
3.168 × 10⁹⁴(95-digit number)
31680904145845214911…01183234334775459841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
6.336 × 10⁹⁴(95-digit number)
63361808291690429823…02366468669550919681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.267 × 10⁹⁵(96-digit number)
12672361658338085964…04732937339101839361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.534 × 10⁹⁵(96-digit number)
25344723316676171929…09465874678203678721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
5.068 × 10⁹⁵(96-digit number)
50689446633352343858…18931749356407357441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.013 × 10⁹⁶(97-digit number)
10137889326670468771…37863498712814714881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.027 × 10⁹⁶(97-digit number)
20275778653340937543…75726997425629429761
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:57,690,897 XPM·at block #6,805,851 · updates every 60s
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