Block #457,888

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 3/24/2014, 5:16:52 AM · Difficulty 10.4205 · 6,351,230 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
7e4aab1a6fcd95efab8eb4f4d3473eeecd086af3162405e295002ca9b5244913

Height

#457,888

Difficulty

10.420471

Transactions

4

Size

1.55 KB

Version

2

Bits

0a6ba3f9

Nonce

42,789

Timestamp

3/24/2014, 5:16:52 AM

Confirmations

6,351,230

Merkle Root

b479280c9889c82cf5d7a87943e05a6ae17e2e41f61c920612fb3531120b31fc
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.

1.716 × 10⁹⁵(96-digit number)
17166730126674751337…98145795941179518081
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
1.716 × 10⁹⁵(96-digit number)
17166730126674751337…98145795941179518081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
3.433 × 10⁹⁵(96-digit number)
34333460253349502674…96291591882359036161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
6.866 × 10⁹⁵(96-digit number)
68666920506699005348…92583183764718072321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.373 × 10⁹⁶(97-digit number)
13733384101339801069…85166367529436144641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.746 × 10⁹⁶(97-digit number)
27466768202679602139…70332735058872289281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
5.493 × 10⁹⁶(97-digit number)
54933536405359204278…40665470117744578561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.098 × 10⁹⁷(98-digit number)
10986707281071840855…81330940235489157121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.197 × 10⁹⁷(98-digit number)
21973414562143681711…62661880470978314241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
4.394 × 10⁹⁷(98-digit number)
43946829124287363423…25323760941956628481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
8.789 × 10⁹⁷(98-digit number)
87893658248574726846…50647521883913256961
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:57,717,001 XPM·at block #6,809,117 · updates every 60s
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