Block #270,283

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 11/23/2013, 8:06:58 PM · Difficulty 9.9518 · 6,525,706 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
6901ed419d81804781026d87b668dd053a281a11728976ec8b16956b20eb93cf

Height

#270,283

Difficulty

9.951840

Transactions

11

Size

7.68 KB

Version

2

Bits

09f3abcc

Nonce

27,264

Timestamp

11/23/2013, 8:06:58 PM

Confirmations

6,525,706

Merkle Root

607b736c62b0dbb90d53b0c47db5360113abb0c87b52c7d61392d5b6bf6eb639
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.

3.321 × 10⁹⁴(95-digit number)
33211013055415583595…64246618256836768001
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
3.321 × 10⁹⁴(95-digit number)
33211013055415583595…64246618256836768001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
6.642 × 10⁹⁴(95-digit number)
66422026110831167190…28493236513673536001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.328 × 10⁹⁵(96-digit number)
13284405222166233438…56986473027347072001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.656 × 10⁹⁵(96-digit number)
26568810444332466876…13972946054694144001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
5.313 × 10⁹⁵(96-digit number)
53137620888664933752…27945892109388288001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.062 × 10⁹⁶(97-digit number)
10627524177732986750…55891784218776576001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.125 × 10⁹⁶(97-digit number)
21255048355465973500…11783568437553152001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
4.251 × 10⁹⁶(97-digit number)
42510096710931947001…23567136875106304001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
8.502 × 10⁹⁶(97-digit number)
85020193421863894003…47134273750212608001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.700 × 10⁹⁷(98-digit number)
17004038684372778800…94268547500425216001
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:57,612,007 XPM·at block #6,795,988 · updates every 60s
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