Block #460,631

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 3/26/2014, 4:16:21 AM · Difficulty 10.4141 · 6,338,724 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
d6b6d5284f939fc7de83c10e580c264605f980c2fca64b4770e74682ce05a611

Height

#460,631

Difficulty

10.414148

Transactions

2

Size

1.84 KB

Version

2

Bits

0a6a05a0

Nonce

46,436

Timestamp

3/26/2014, 4:16:21 AM

Confirmations

6,338,724

Merkle Root

71c46968e899c80b75b63a7171c6c3bc5a41d22ee90cbb23b8a96c0c999fd75f
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.

2.609 × 10⁹⁹(100-digit number)
26094206397146840313…37045877276462230561
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
2.609 × 10⁹⁹(100-digit number)
26094206397146840313…37045877276462230561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
5.218 × 10⁹⁹(100-digit number)
52188412794293680626…74091754552924461121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.043 × 10¹⁰⁰(101-digit number)
10437682558858736125…48183509105848922241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.087 × 10¹⁰⁰(101-digit number)
20875365117717472250…96367018211697844481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
4.175 × 10¹⁰⁰(101-digit number)
41750730235434944501…92734036423395688961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
8.350 × 10¹⁰⁰(101-digit number)
83501460470869889002…85468072846791377921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.670 × 10¹⁰¹(102-digit number)
16700292094173977800…70936145693582755841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
3.340 × 10¹⁰¹(102-digit number)
33400584188347955601…41872291387165511681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
6.680 × 10¹⁰¹(102-digit number)
66801168376695911202…83744582774331023361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.336 × 10¹⁰²(103-digit number)
13360233675339182240…67489165548662046721
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:57,638,885 XPM·at block #6,799,354 · updates every 60s
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