Block #3,009,265

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 1/14/2019, 12:31:21 PM · Difficulty 11.2008 · 3,833,627 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
5559a3f7e9a0c6f36ab81bd0ec92d0a4743f90f3edad7648572007785db83be7

Height

#3,009,265

Difficulty

11.200798

Transactions

4

Size

1.29 KB

Version

2

Bits

0b336778

Nonce

1,060,424,565

Timestamp

1/14/2019, 12:31:21 PM

Confirmations

3,833,627

Merkle Root

238934f085576ce843a19c91d31d0e873f5708b68b86b06428478b7612dc41cd
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.

2.584 × 10⁹⁵(96-digit number)
25845811275657552967…81175467073577516381
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
2.584 × 10⁹⁵(96-digit number)
25845811275657552967…81175467073577516381
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
5.169 × 10⁹⁵(96-digit number)
51691622551315105935…62350934147155032761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.033 × 10⁹⁶(97-digit number)
10338324510263021187…24701868294310065521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.067 × 10⁹⁶(97-digit number)
20676649020526042374…49403736588620131041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
4.135 × 10⁹⁶(97-digit number)
41353298041052084748…98807473177240262081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
8.270 × 10⁹⁶(97-digit number)
82706596082104169496…97614946354480524161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.654 × 10⁹⁷(98-digit number)
16541319216420833899…95229892708961048321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
3.308 × 10⁹⁷(98-digit number)
33082638432841667798…90459785417922096641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
6.616 × 10⁹⁷(98-digit number)
66165276865683335597…80919570835844193281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.323 × 10⁹⁸(99-digit number)
13233055373136667119…61839141671688386561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
2.646 × 10⁹⁸(99-digit number)
26466110746273334238…23678283343376773121
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:57,987,483 XPM·at block #6,842,891 · updates every 60s
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