Block #365,545

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 1/18/2014, 8:00:02 PM · Difficulty 10.4244 · 6,433,024 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
3efb5cedf25bb97d10d5a73676f22110ee7c0d7665dbd91a71a7a947a9f4d529

Height

#365,545

Difficulty

10.424356

Transactions

5

Size

1.80 KB

Version

2

Bits

0a6ca29c

Nonce

70,263

Timestamp

1/18/2014, 8:00:02 PM

Confirmations

6,433,024

Merkle Root

668dabf3731827c42f757a1471f3ee419ba12f1ec4678d9cd0fbaa43af05d92d
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.

7.592 × 10⁹⁷(98-digit number)
75929955863500879670…34356088989757346481
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
7.592 × 10⁹⁷(98-digit number)
75929955863500879670…34356088989757346481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.518 × 10⁹⁸(99-digit number)
15185991172700175934…68712177979514692961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
3.037 × 10⁹⁸(99-digit number)
30371982345400351868…37424355959029385921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
6.074 × 10⁹⁸(99-digit number)
60743964690800703736…74848711918058771841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.214 × 10⁹⁹(100-digit number)
12148792938160140747…49697423836117543681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.429 × 10⁹⁹(100-digit number)
24297585876320281494…99394847672235087361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
4.859 × 10⁹⁹(100-digit number)
48595171752640562989…98789695344470174721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
9.719 × 10⁹⁹(100-digit number)
97190343505281125978…97579390688940349441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.943 × 10¹⁰⁰(101-digit number)
19438068701056225195…95158781377880698881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
3.887 × 10¹⁰⁰(101-digit number)
38876137402112450391…90317562755761397761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
7.775 × 10¹⁰⁰(101-digit number)
77752274804224900782…80635125511522795521
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:57,632,570 XPM·at block #6,798,568 · updates every 60s
xpmprime.info is a work in progress. If you enjoy using this service you can support this project with a Primecoin donation.