Block #466,723

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 3/30/2014, 8:37:28 AM · Difficulty 10.4253 · 6,327,563 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
19d47a1e15595aa86dec9f5b2a6dcbc9ea90d8f00ece26f048924a4daef850f3

Height

#466,723

Difficulty

10.425302

Transactions

7

Size

2.73 KB

Version

2

Bits

0a6ce09c

Nonce

159,095

Timestamp

3/30/2014, 8:37:28 AM

Confirmations

6,327,563

Merkle Root

62675ce36ada527c2d7ddc15dd1608a4e637c464957179ad2984f02cec3d8346
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.

8.112 × 10¹⁰²(103-digit number)
81126996766826203261…88316097447740816001
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
8.112 × 10¹⁰²(103-digit number)
81126996766826203261…88316097447740816001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.622 × 10¹⁰³(104-digit number)
16225399353365240652…76632194895481632001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
3.245 × 10¹⁰³(104-digit number)
32450798706730481304…53264389790963264001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
6.490 × 10¹⁰³(104-digit number)
64901597413460962609…06528779581926528001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.298 × 10¹⁰⁴(105-digit number)
12980319482692192521…13057559163853056001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.596 × 10¹⁰⁴(105-digit number)
25960638965384385043…26115118327706112001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
5.192 × 10¹⁰⁴(105-digit number)
51921277930768770087…52230236655412224001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.038 × 10¹⁰⁵(106-digit number)
10384255586153754017…04460473310824448001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.076 × 10¹⁰⁵(106-digit number)
20768511172307508034…08920946621648896001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
4.153 × 10¹⁰⁵(106-digit number)
41537022344615016069…17841893243297792001
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:57,598,318 XPM·at block #6,794,285 · updates every 60s
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