Block #3,546,823

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 2/6/2020, 6:10:22 AM · Difficulty 10.9340 · 3,286,798 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
e3a795169efec4fd0f808b25fb8e47cd5e22406c4b44aa8569c35b0790f1dfd7

Height

#3,546,823

Difficulty

10.934036

Transactions

3

Size

767 B

Version

2

Bits

0aef1cfc

Nonce

1,200,823,833

Timestamp

2/6/2020, 6:10:22 AM

Confirmations

3,286,798

Merkle Root

d817399ad3e254850a0a8f4d9d57074788b2eff67e38e076ffcc62c2e82357b0
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.

4.372 × 10⁹³(94-digit number)
43721439438739586075…21459063452916121601
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
4.372 × 10⁹³(94-digit number)
43721439438739586075…21459063452916121601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
8.744 × 10⁹³(94-digit number)
87442878877479172151…42918126905832243201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.748 × 10⁹⁴(95-digit number)
17488575775495834430…85836253811664486401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
3.497 × 10⁹⁴(95-digit number)
34977151550991668860…71672507623328972801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
6.995 × 10⁹⁴(95-digit number)
69954303101983337721…43345015246657945601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.399 × 10⁹⁵(96-digit number)
13990860620396667544…86690030493315891201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.798 × 10⁹⁵(96-digit number)
27981721240793335088…73380060986631782401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
5.596 × 10⁹⁵(96-digit number)
55963442481586670177…46760121973263564801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.119 × 10⁹⁶(97-digit number)
11192688496317334035…93520243946527129601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.238 × 10⁹⁶(97-digit number)
22385376992634668070…87040487893054259201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
4.477 × 10⁹⁶(97-digit number)
44770753985269336141…74080975786108518401
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:57,913,177 XPM·at block #6,833,620 · updates every 60s
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