Block #2,632,403

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 4/27/2018, 7:29:51 PM · Difficulty 11.1723 · 4,200,646 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
8b3065044e3e12a9c7a32dc44b681a408456a0162cf75c0f90e44fbdde9020a1

Height

#2,632,403

Difficulty

11.172329

Transactions

4

Size

2.73 KB

Version

2

Bits

0b2c1dc8

Nonce

1,585,589,853

Timestamp

4/27/2018, 7:29:51 PM

Confirmations

4,200,646

Merkle Root

ab70b84bcc19cd792954ecd196a2e36ee5ec31a976861085af6cfb7078f6ed14
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.

9.061 × 10⁹²(93-digit number)
90612665467610406676…47737184956463148161
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
9.061 × 10⁹²(93-digit number)
90612665467610406676…47737184956463148161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.812 × 10⁹³(94-digit number)
18122533093522081335…95474369912926296321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
3.624 × 10⁹³(94-digit number)
36245066187044162670…90948739825852592641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
7.249 × 10⁹³(94-digit number)
72490132374088325341…81897479651705185281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.449 × 10⁹⁴(95-digit number)
14498026474817665068…63794959303410370561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.899 × 10⁹⁴(95-digit number)
28996052949635330136…27589918606820741121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
5.799 × 10⁹⁴(95-digit number)
57992105899270660273…55179837213641482241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.159 × 10⁹⁵(96-digit number)
11598421179854132054…10359674427282964481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.319 × 10⁹⁵(96-digit number)
23196842359708264109…20719348854565928961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
4.639 × 10⁹⁵(96-digit number)
46393684719416528218…41438697709131857921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
9.278 × 10⁹⁵(96-digit number)
92787369438833056437…82877395418263715841
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 11 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
RareChain length 11

Approximately 1 in 1,000 blocks. Noteworthy discoveries.

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:57,908,572 XPM·at block #6,833,048 · updates every 60s
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