Block #430,022

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 3/5/2014, 5:46:10 AM · Difficulty 10.3394 · 6,376,230 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
688a322d66d6cb175a6bd7cb44a8fbe9f7f4f301f96c2a269e209d3f65d2f553

Height

#430,022

Difficulty

10.339441

Transactions

4

Size

3.30 KB

Version

2

Bits

0a56e594

Nonce

218,133

Timestamp

3/5/2014, 5:46:10 AM

Confirmations

6,376,230

Merkle Root

01623a78b4a0165016e205755a302a6ae0bfdce9969369cc368911a0c17e8db3
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.

3.196 × 10⁹⁵(96-digit number)
31969735326775078600…80139843201323924121
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
3.196 × 10⁹⁵(96-digit number)
31969735326775078600…80139843201323924121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
6.393 × 10⁹⁵(96-digit number)
63939470653550157200…60279686402647848241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.278 × 10⁹⁶(97-digit number)
12787894130710031440…20559372805295696481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.557 × 10⁹⁶(97-digit number)
25575788261420062880…41118745610591392961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
5.115 × 10⁹⁶(97-digit number)
51151576522840125760…82237491221182785921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.023 × 10⁹⁷(98-digit number)
10230315304568025152…64474982442365571841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.046 × 10⁹⁷(98-digit number)
20460630609136050304…28949964884731143681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
4.092 × 10⁹⁷(98-digit number)
40921261218272100608…57899929769462287361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
8.184 × 10⁹⁷(98-digit number)
81842522436544201216…15799859538924574721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.636 × 10⁹⁸(99-digit number)
16368504487308840243…31599719077849149441
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:57,694,099 XPM·at block #6,806,251 · updates every 60s
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