Block #2,224,062

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 7/26/2017, 6:01:39 PM · Difficulty 10.9467 · 4,600,894 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
a17f986d50cb94300ac5a464359d358f48118586ded11195961dbbacf13db825

Height

#2,224,062

Difficulty

10.946669

Transactions

7

Size

2.32 KB

Version

2

Bits

0af258df

Nonce

963,017,095

Timestamp

7/26/2017, 6:01:39 PM

Confirmations

4,600,894

Merkle Root

52f1158f1f5756ac67f737f8a3dfdd8c753bc24aef0add5a0b334ca65bcaf692
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.

8.264 × 10⁹³(94-digit number)
82642997672505637707…26156387577010395841
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
8.264 × 10⁹³(94-digit number)
82642997672505637707…26156387577010395841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.652 × 10⁹⁴(95-digit number)
16528599534501127541…52312775154020791681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
3.305 × 10⁹⁴(95-digit number)
33057199069002255082…04625550308041583361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
6.611 × 10⁹⁴(95-digit number)
66114398138004510165…09251100616083166721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.322 × 10⁹⁵(96-digit number)
13222879627600902033…18502201232166333441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.644 × 10⁹⁵(96-digit number)
26445759255201804066…37004402464332666881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
5.289 × 10⁹⁵(96-digit number)
52891518510403608132…74008804928665333761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.057 × 10⁹⁶(97-digit number)
10578303702080721626…48017609857330667521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.115 × 10⁹⁶(97-digit number)
21156607404161443253…96035219714661335041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
4.231 × 10⁹⁶(97-digit number)
42313214808322886506…92070439429322670081
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:57,843,727 XPM·at block #6,824,955 · updates every 60s
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