Block #2,469,771

1CCLength 11★★★☆☆

Cunningham Chain of the First Kind · Discovered 1/12/2018, 5:12:03 PM · Difficulty 10.9606 · 4,372,559 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
e662a644d8928e6812b4e83a7713391be9464334ce9979898bb066c036e7e7f5

Height

#2,469,771

Difficulty

10.960580

Transactions

10

Size

2.82 KB

Version

2

Bits

0af5e88d

Nonce

366,877,649

Timestamp

1/12/2018, 5:12:03 PM

Confirmations

4,372,559

Merkle Root

38fa33f643837e95084e1809aa0fac538099a5720b7963204a4ca5bb29ebb7d4
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.

2.079 × 10⁹⁴(95-digit number)
20796286218214348086…27837300368507330559
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
2.079 × 10⁹⁴(95-digit number)
20796286218214348086…27837300368507330559
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
4.159 × 10⁹⁴(95-digit number)
41592572436428696172…55674600737014661119
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
8.318 × 10⁹⁴(95-digit number)
83185144872857392345…11349201474029322239
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
1.663 × 10⁹⁵(96-digit number)
16637028974571478469…22698402948058644479
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
3.327 × 10⁹⁵(96-digit number)
33274057949142956938…45396805896117288959
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
6.654 × 10⁹⁵(96-digit number)
66548115898285913876…90793611792234577919
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
1.330 × 10⁹⁶(97-digit number)
13309623179657182775…81587223584469155839
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
2.661 × 10⁹⁶(97-digit number)
26619246359314365550…63174447168938311679
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
5.323 × 10⁹⁶(97-digit number)
53238492718628731101…26348894337876623359
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
1.064 × 10⁹⁷(98-digit number)
10647698543725746220…52697788675753246719
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
11
2^10 × origin − 1
2.129 × 10⁹⁷(98-digit number)
21295397087451492440…05395577351506493439
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:57,983,048 XPM·at block #6,842,329 · updates every 60s
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