Block #3,558,162

1CCLength 10★★☆☆☆

Cunningham Chain of the First Kind · Discovered 2/15/2020, 2:50:29 AM · Difficulty 10.9130 · 3,252,871 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
771c1b02bcdb621606f61a38363691c6510f7e7ab2d6e4044d4adc6d69c6f7b3

Height

#3,558,162

Difficulty

10.912959

Transactions

11

Size

2.07 KB

Version

2

Bits

0ae9b7aa

Nonce

1,926,074,858

Timestamp

2/15/2020, 2:50:29 AM

Confirmations

3,252,871

Merkle Root

a7bc1a9feda7e41fcb3c658c6b8cf0650e23d43487c05133dd7e246494910c6b
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.

1.656 × 10⁹³(94-digit number)
16568794884417107724…56150181107778303999
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
1.656 × 10⁹³(94-digit number)
16568794884417107724…56150181107778303999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
3.313 × 10⁹³(94-digit number)
33137589768834215449…12300362215556607999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
6.627 × 10⁹³(94-digit number)
66275179537668430899…24600724431113215999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
1.325 × 10⁹⁴(95-digit number)
13255035907533686179…49201448862226431999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
2.651 × 10⁹⁴(95-digit number)
26510071815067372359…98402897724452863999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
5.302 × 10⁹⁴(95-digit number)
53020143630134744719…96805795448905727999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
1.060 × 10⁹⁵(96-digit number)
10604028726026948943…93611590897811455999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
2.120 × 10⁹⁵(96-digit number)
21208057452053897887…87223181795622911999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
4.241 × 10⁹⁵(96-digit number)
42416114904107795775…74446363591245823999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
8.483 × 10⁹⁵(96-digit number)
84832229808215591551…48892727182491647999
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 10 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
UncommonChain length 10

Roughly 1 in 100 blocks. Solid but expected in a healthy network.

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:57,732,373 XPM·at block #6,811,032 · updates every 60s
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