Block #302,062

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/9/2013, 2:33:12 PM · Difficulty 9.9926 · 6,515,875 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
1664ec7697c9e3e4463bcf93f60dc2f8167859b6b69f3597452f60e00a8b5b23

Height

#302,062

Difficulty

9.992611

Transactions

7

Size

2.06 KB

Version

2

Bits

09fe1bc5

Nonce

431,530

Timestamp

12/9/2013, 2:33:12 PM

Confirmations

6,515,875

Merkle Root

27c9059d1ac49cd6bdb60bd21b977487d1428474cf93b01889b7cee87407c4a5
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.

5.727 × 10⁹⁴(95-digit number)
57270586776584778456…82705063795298676801
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
5.727 × 10⁹⁴(95-digit number)
57270586776584778456…82705063795298676801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.145 × 10⁹⁵(96-digit number)
11454117355316955691…65410127590597353601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.290 × 10⁹⁵(96-digit number)
22908234710633911382…30820255181194707201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
4.581 × 10⁹⁵(96-digit number)
45816469421267822765…61640510362389414401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
9.163 × 10⁹⁵(96-digit number)
91632938842535645530…23281020724778828801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.832 × 10⁹⁶(97-digit number)
18326587768507129106…46562041449557657601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
3.665 × 10⁹⁶(97-digit number)
36653175537014258212…93124082899115315201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
7.330 × 10⁹⁶(97-digit number)
73306351074028516424…86248165798230630401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.466 × 10⁹⁷(98-digit number)
14661270214805703284…72496331596461260801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.932 × 10⁹⁷(98-digit number)
29322540429611406569…44992663192922521601
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:57,787,561 XPM·at block #6,817,936 · updates every 60s
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