Block #449,345

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 3/18/2014, 12:56:38 PM · Difficulty 10.3722 · 6,367,868 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
d9a30cc9f9478963efd3d0f29c0ecaa5af1346ba25a12f46e71f1bed73feff60

Height

#449,345

Difficulty

10.372194

Transactions

2

Size

856 B

Version

2

Bits

0a5f4821

Nonce

50,834,290

Timestamp

3/18/2014, 12:56:38 PM

Confirmations

6,367,868

Merkle Root

3cf8e5200099fbef1fc9ebadacb6b1c138ec6afe2d92f36b8c371c2f9a5b763e
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.

1.907 × 10⁹⁵(96-digit number)
19075109308278541918…72061563707550622561
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
1.907 × 10⁹⁵(96-digit number)
19075109308278541918…72061563707550622561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
3.815 × 10⁹⁵(96-digit number)
38150218616557083837…44123127415101245121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
7.630 × 10⁹⁵(96-digit number)
76300437233114167675…88246254830202490241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.526 × 10⁹⁶(97-digit number)
15260087446622833535…76492509660404980481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
3.052 × 10⁹⁶(97-digit number)
30520174893245667070…52985019320809960961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
6.104 × 10⁹⁶(97-digit number)
61040349786491334140…05970038641619921921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.220 × 10⁹⁷(98-digit number)
12208069957298266828…11940077283239843841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.441 × 10⁹⁷(98-digit number)
24416139914596533656…23880154566479687681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
4.883 × 10⁹⁷(98-digit number)
48832279829193067312…47760309132959375361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
9.766 × 10⁹⁷(98-digit number)
97664559658386134625…95520618265918750721
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:57,781,743 XPM·at block #6,817,212 · updates every 60s
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