Block #3,006,392

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 1/12/2019, 1:02:28 PM · Difficulty 11.1968 · 3,832,749 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
1efa02b988cdc8e07f3c1504f7f11985931cd220c6c5b26c2626fca3519bd2a8

Height

#3,006,392

Difficulty

11.196779

Transactions

13

Size

3.56 KB

Version

2

Bits

0b326015

Nonce

1,607,719

Timestamp

1/12/2019, 1:02:28 PM

Confirmations

3,832,749

Merkle Root

db2957a002fc8f83de9f23cf3b32fcde6937e20aaf4460ec4574df5bb4e6f13d
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.

8.736 × 10⁹⁵(96-digit number)
87365132437303813866…04684592693205708801
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
8.736 × 10⁹⁵(96-digit number)
87365132437303813866…04684592693205708801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.747 × 10⁹⁶(97-digit number)
17473026487460762773…09369185386411417601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
3.494 × 10⁹⁶(97-digit number)
34946052974921525546…18738370772822835201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
6.989 × 10⁹⁶(97-digit number)
69892105949843051092…37476741545645670401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.397 × 10⁹⁷(98-digit number)
13978421189968610218…74953483091291340801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.795 × 10⁹⁷(98-digit number)
27956842379937220437…49906966182582681601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
5.591 × 10⁹⁷(98-digit number)
55913684759874440874…99813932365165363201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.118 × 10⁹⁸(99-digit number)
11182736951974888174…99627864730330726401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.236 × 10⁹⁸(99-digit number)
22365473903949776349…99255729460661452801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
4.473 × 10⁹⁸(99-digit number)
44730947807899552699…98511458921322905601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
8.946 × 10⁹⁸(99-digit number)
89461895615799105398…97022917842645811201
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:57,957,407 XPM·at block #6,839,140 · updates every 60s
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