Block #302,119

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 12/9/2013, 3:26:02 PM · Difficulty 9.9926 · 6,512,872 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
85326e9c404db284d8e322b01daf0e7b1fd74f5d42f15c8a14149884addcf78b

Height

#302,119

Difficulty

9.992617

Transactions

17

Size

12.03 KB

Version

2

Bits

09fe1c22

Nonce

243,609

Timestamp

12/9/2013, 3:26:02 PM

Confirmations

6,512,872

Merkle Root

88960dabff2a2e0e7de74ac5acd4b496d83b9622454e4a4c4330f916b73d46dd
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.

5.971 × 10⁹⁶(97-digit number)
59714435411070032716…98277417394731700661
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
5.971 × 10⁹⁶(97-digit number)
59714435411070032716…98277417394731700661
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.194 × 10⁹⁷(98-digit number)
11942887082214006543…96554834789463401321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.388 × 10⁹⁷(98-digit number)
23885774164428013086…93109669578926802641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
4.777 × 10⁹⁷(98-digit number)
47771548328856026173…86219339157853605281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
9.554 × 10⁹⁷(98-digit number)
95543096657712052346…72438678315707210561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.910 × 10⁹⁸(99-digit number)
19108619331542410469…44877356631414421121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
3.821 × 10⁹⁸(99-digit number)
38217238663084820938…89754713262828842241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
7.643 × 10⁹⁸(99-digit number)
76434477326169641877…79509426525657684481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.528 × 10⁹⁹(100-digit number)
15286895465233928375…59018853051315368961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
3.057 × 10⁹⁹(100-digit number)
30573790930467856750…18037706102630737921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
6.114 × 10⁹⁹(100-digit number)
61147581860935713501…36075412205261475841
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 11 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
RareChain length 11

Approximately 1 in 1,000 blocks. Noteworthy discoveries.

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:57,764,013 XPM·at block #6,814,990 · updates every 60s
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