Block #3,550,926

1CCLength 11★★★☆☆

Cunningham Chain of the First Kind · Discovered 2/9/2020, 7:25:38 AM · Difficulty 10.9303 · 3,288,802 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
48c2a452bd8991a284edcc93df54f18eee7673e5c5e1777a5e25b8f114a129c2

Height

#3,550,926

Difficulty

10.930284

Transactions

2

Size

1.14 KB

Version

2

Bits

0aee2718

Nonce

1,072,902,329

Timestamp

2/9/2020, 7:25:38 AM

Confirmations

3,288,802

Merkle Root

cf4c94583990edc5d92479aebe1698b7d4d312dec363267a819ef39fef89effd
Transactions (2)
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.

3.660 × 10⁹⁶(97-digit number)
36609869709173535413…18093418870784883199
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
3.660 × 10⁹⁶(97-digit number)
36609869709173535413…18093418870784883199
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
7.321 × 10⁹⁶(97-digit number)
73219739418347070827…36186837741569766399
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
1.464 × 10⁹⁷(98-digit number)
14643947883669414165…72373675483139532799
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
2.928 × 10⁹⁷(98-digit number)
29287895767338828331…44747350966279065599
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
5.857 × 10⁹⁷(98-digit number)
58575791534677656662…89494701932558131199
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
1.171 × 10⁹⁸(99-digit number)
11715158306935531332…78989403865116262399
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
2.343 × 10⁹⁸(99-digit number)
23430316613871062664…57978807730232524799
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
4.686 × 10⁹⁸(99-digit number)
46860633227742125329…15957615460465049599
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
9.372 × 10⁹⁸(99-digit number)
93721266455484250659…31915230920930099199
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
1.874 × 10⁹⁹(100-digit number)
18744253291096850131…63830461841860198399
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
11
2^10 × origin − 1
3.748 × 10⁹⁹(100-digit number)
37488506582193700263…27660923683720396799
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 First 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 1CC formula:

1CC: p₁ (first prime), p₂ = 2p₁ + 1, p₃ = 2p₂ + 1, …
Circulating Supply:57,962,109 XPM·at block #6,839,727 · updates every 60s
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