Block #879,382

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/2/2015, 3:28:08 PM · Difficulty 10.9626 · 5,947,338 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
98f64b6281b9eddb6e068f800ba02cce888548a09e887f81e0930dd8b43cfb6d

Height

#879,382

Difficulty

10.962601

Transactions

17

Size

4.02 KB

Version

2

Bits

0af66d02

Nonce

238,724,942

Timestamp

1/2/2015, 3:28:08 PM

Confirmations

5,947,338

Merkle Root

dd8729ae58dd950a4edeae3a37c1658f6948f7104d2c41f2fcd190f0c3153717
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.

5.051 × 10⁹⁵(96-digit number)
50515191709857289349…31315594828448719081
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
5.051 × 10⁹⁵(96-digit number)
50515191709857289349…31315594828448719081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.010 × 10⁹⁶(97-digit number)
10103038341971457869…62631189656897438161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.020 × 10⁹⁶(97-digit number)
20206076683942915739…25262379313794876321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
4.041 × 10⁹⁶(97-digit number)
40412153367885831479…50524758627589752641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
8.082 × 10⁹⁶(97-digit number)
80824306735771662959…01049517255179505281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.616 × 10⁹⁷(98-digit number)
16164861347154332591…02099034510359010561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
3.232 × 10⁹⁷(98-digit number)
32329722694308665183…04198069020718021121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
6.465 × 10⁹⁷(98-digit number)
64659445388617330367…08396138041436042241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.293 × 10⁹⁸(99-digit number)
12931889077723466073…16792276082872084481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.586 × 10⁹⁸(99-digit number)
25863778155446932147…33584552165744168961
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:57,857,914 XPM·at block #6,826,719 · updates every 60s
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