Block #449,625

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 3/18/2014, 5:27:33 PM · Difficulty 10.3731 · 6,375,149 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
f5322b62c681353f554b4d7579c58336e675feb40103772522b73b45daeeba13

Height

#449,625

Difficulty

10.373110

Transactions

2

Size

679 B

Version

2

Bits

0a5f8429

Nonce

229,828

Timestamp

3/18/2014, 5:27:33 PM

Confirmations

6,375,149

Merkle Root

ca16239ddcfc955eb6f5511101086a01b778d993c7444fd31b0821c7f9eb3f80
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.

8.425 × 10⁹⁷(98-digit number)
84250343362524627945…52038897578483635201
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
8.425 × 10⁹⁷(98-digit number)
84250343362524627945…52038897578483635201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.685 × 10⁹⁸(99-digit number)
16850068672504925589…04077795156967270401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
3.370 × 10⁹⁸(99-digit number)
33700137345009851178…08155590313934540801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
6.740 × 10⁹⁸(99-digit number)
67400274690019702356…16311180627869081601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.348 × 10⁹⁹(100-digit number)
13480054938003940471…32622361255738163201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.696 × 10⁹⁹(100-digit number)
26960109876007880942…65244722511476326401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
5.392 × 10⁹⁹(100-digit number)
53920219752015761885…30489445022952652801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.078 × 10¹⁰⁰(101-digit number)
10784043950403152377…60978890045905305601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.156 × 10¹⁰⁰(101-digit number)
21568087900806304754…21957780091810611201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
4.313 × 10¹⁰⁰(101-digit number)
43136175801612609508…43915560183621222401
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:57,842,264 XPM·at block #6,824,773 · updates every 60s
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