Block #790,683

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 10/31/2014, 12:23:52 PM · Difficulty 10.9733 · 6,011,868 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
a1f9905d45602bc1798bf4169373e23a6235b791bbd0427dd267cdbb4f2fb617

Height

#790,683

Difficulty

10.973291

Transactions

5

Size

1.20 KB

Version

2

Bits

0af92994

Nonce

1,429,385,736

Timestamp

10/31/2014, 12:23:52 PM

Confirmations

6,011,868

Merkle Root

e70e8393d201a9ff8489d1c28d809190e91fbba4fba1d383530c82aa8d5670ac
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.

6.124 × 10⁹⁶(97-digit number)
61244675074501210291…06156243481777422401
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
6.124 × 10⁹⁶(97-digit number)
61244675074501210291…06156243481777422401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.224 × 10⁹⁷(98-digit number)
12248935014900242058…12312486963554844801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.449 × 10⁹⁷(98-digit number)
24497870029800484116…24624973927109689601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
4.899 × 10⁹⁷(98-digit number)
48995740059600968233…49249947854219379201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
9.799 × 10⁹⁷(98-digit number)
97991480119201936466…98499895708438758401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.959 × 10⁹⁸(99-digit number)
19598296023840387293…96999791416877516801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
3.919 × 10⁹⁸(99-digit number)
39196592047680774586…93999582833755033601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
7.839 × 10⁹⁸(99-digit number)
78393184095361549173…87999165667510067201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.567 × 10⁹⁹(100-digit number)
15678636819072309834…75998331335020134401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
3.135 × 10⁹⁹(100-digit number)
31357273638144619669…51996662670040268801
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:57,664,420 XPM·at block #6,802,550 · updates every 60s
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