Block #4,024,369

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/6/2021, 8:53:04 AM · Difficulty 10.8413 · 2,791,941 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
4c0b5449a228837e9cc2757c094e49ef708d2a4d97ba8ec1567ee55dc595b3f4

Height

#4,024,369

Difficulty

10.841319

Transactions

7

Size

2.68 KB

Version

2

Bits

0ad760b6

Nonce

1,714,420,668

Timestamp

1/6/2021, 8:53:04 AM

Confirmations

2,791,941

Merkle Root

975e2cc3810fb3183dd8f1f65cc2857ae6204fddef81e1188fa77e5ee24c8246
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.

5.329 × 10⁹³(94-digit number)
53299923944427742256…84280523203958060321
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
5.329 × 10⁹³(94-digit number)
53299923944427742256…84280523203958060321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.065 × 10⁹⁴(95-digit number)
10659984788885548451…68561046407916120641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.131 × 10⁹⁴(95-digit number)
21319969577771096902…37122092815832241281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
4.263 × 10⁹⁴(95-digit number)
42639939155542193805…74244185631664482561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
8.527 × 10⁹⁴(95-digit number)
85279878311084387610…48488371263328965121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.705 × 10⁹⁵(96-digit number)
17055975662216877522…96976742526657930241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
3.411 × 10⁹⁵(96-digit number)
34111951324433755044…93953485053315860481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
6.822 × 10⁹⁵(96-digit number)
68223902648867510088…87906970106631720961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.364 × 10⁹⁶(97-digit number)
13644780529773502017…75813940213263441921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.728 × 10⁹⁶(97-digit number)
27289561059547004035…51627880426526883841
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 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
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 2CC formula:

2CC: p₁ (first prime), p₂ = 2p₁ − 1, p₃ = 2p₂ − 1, …
Circulating Supply:57,774,601 XPM·at block #6,816,309 · updates every 60s
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