Block #448,341

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 3/17/2014, 8:38:19 PM · Difficulty 10.3684 · 6,362,019 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
b3ab78c5c37dc2f9037e7350f916ee4919d91b44aeffeb38d9fdd3424288f345

Height

#448,341

Difficulty

10.368432

Transactions

3

Size

1.70 KB

Version

2

Bits

0a5e5190

Nonce

102,898

Timestamp

3/17/2014, 8:38:19 PM

Confirmations

6,362,019

Merkle Root

f2fa899d10cf1f2fcc853d72d8e756afb679cd9836c198b3cc6e2334a198b619
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.

1.269 × 10⁹⁴(95-digit number)
12693715871606553107…74534543512879863081
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
1.269 × 10⁹⁴(95-digit number)
12693715871606553107…74534543512879863081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.538 × 10⁹⁴(95-digit number)
25387431743213106215…49069087025759726161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
5.077 × 10⁹⁴(95-digit number)
50774863486426212430…98138174051519452321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.015 × 10⁹⁵(96-digit number)
10154972697285242486…96276348103038904641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.030 × 10⁹⁵(96-digit number)
20309945394570484972…92552696206077809281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
4.061 × 10⁹⁵(96-digit number)
40619890789140969944…85105392412155618561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
8.123 × 10⁹⁵(96-digit number)
81239781578281939888…70210784824311237121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.624 × 10⁹⁶(97-digit number)
16247956315656387977…40421569648622474241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
3.249 × 10⁹⁶(97-digit number)
32495912631312775955…80843139297244948481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
6.499 × 10⁹⁶(97-digit number)
64991825262625551910…61686278594489896961
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:57,726,955 XPM·at block #6,810,359 · updates every 60s
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