Block #2,235,023

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 8/3/2017, 10:57:06 AM · Difficulty 10.9456 · 4,609,964 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
3dafa816145737cc6e04ce549124ccc6cce0c556e9c36b90ed8f5238526afc7f

Height

#2,235,023

Difficulty

10.945561

Transactions

2

Size

2.01 KB

Version

2

Bits

0af21048

Nonce

49,588,280

Timestamp

8/3/2017, 10:57:06 AM

Confirmations

4,609,964

Merkle Root

aecc3217789c86eae45089161157547087122006f7c833498d16e435aeb2713e
Transactions (2)
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.

3.848 × 10⁹⁴(95-digit number)
38485484358516438982…70349992035576313401
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
3.848 × 10⁹⁴(95-digit number)
38485484358516438982…70349992035576313401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
7.697 × 10⁹⁴(95-digit number)
76970968717032877965…40699984071152626801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.539 × 10⁹⁵(96-digit number)
15394193743406575593…81399968142305253601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
3.078 × 10⁹⁵(96-digit number)
30788387486813151186…62799936284610507201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
6.157 × 10⁹⁵(96-digit number)
61576774973626302372…25599872569221014401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.231 × 10⁹⁶(97-digit number)
12315354994725260474…51199745138442028801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.463 × 10⁹⁶(97-digit number)
24630709989450520949…02399490276884057601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
4.926 × 10⁹⁶(97-digit number)
49261419978901041898…04798980553768115201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
9.852 × 10⁹⁶(97-digit number)
98522839957802083796…09597961107536230401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.970 × 10⁹⁷(98-digit number)
19704567991560416759…19195922215072460801
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:58,004,315 XPM·at block #6,844,986 · updates every 60s
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