Block #4,057,034

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/29/2021, 8:14:53 PM · Difficulty 10.8024 · 2,760,223 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
50e708aa8017e9dd5b79f187ada13a9f5f0b8a31df6ce8d41292f78f01b55339

Height

#4,057,034

Difficulty

10.802353

Transactions

3

Size

653 B

Version

2

Bits

0acd66fb

Nonce

923,738,000

Timestamp

1/29/2021, 8:14:53 PM

Confirmations

2,760,223

Merkle Root

06a2f53dbdd7119dc224969766d09c162cae75693a11c4e33f3dd983ec18fb92
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.

2.765 × 10⁹⁵(96-digit number)
27657354050124071030…62853164210388844481
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
2.765 × 10⁹⁵(96-digit number)
27657354050124071030…62853164210388844481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
5.531 × 10⁹⁵(96-digit number)
55314708100248142061…25706328420777688961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.106 × 10⁹⁶(97-digit number)
11062941620049628412…51412656841555377921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.212 × 10⁹⁶(97-digit number)
22125883240099256824…02825313683110755841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
4.425 × 10⁹⁶(97-digit number)
44251766480198513648…05650627366221511681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
8.850 × 10⁹⁶(97-digit number)
88503532960397027297…11301254732443023361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.770 × 10⁹⁷(98-digit number)
17700706592079405459…22602509464886046721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
3.540 × 10⁹⁷(98-digit number)
35401413184158810919…45205018929772093441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
7.080 × 10⁹⁷(98-digit number)
70802826368317621838…90410037859544186881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.416 × 10⁹⁸(99-digit number)
14160565273663524367…80820075719088373761
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:57,782,091 XPM·at block #6,817,256 · updates every 60s
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