Block #363,927

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/17/2014, 5:52:57 PM · Difficulty 10.4175 · 6,441,928 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
47e585055bd634b83184c989e043442c5ee3385e5bce46b0dc08fe684f6da54a

Height

#363,927

Difficulty

10.417491

Transactions

5

Size

1.65 KB

Version

2

Bits

0a6ae0b4

Nonce

11,780

Timestamp

1/17/2014, 5:52:57 PM

Confirmations

6,441,928

Merkle Root

493a3af3d1507f6a80ca461c6b1bebb6b6c8edd2e3b81f49626d54c42ebc3c81
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.

6.435 × 10⁹³(94-digit number)
64359155323592778630…56843734163034906881
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
6.435 × 10⁹³(94-digit number)
64359155323592778630…56843734163034906881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.287 × 10⁹⁴(95-digit number)
12871831064718555726…13687468326069813761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.574 × 10⁹⁴(95-digit number)
25743662129437111452…27374936652139627521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
5.148 × 10⁹⁴(95-digit number)
51487324258874222904…54749873304279255041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.029 × 10⁹⁵(96-digit number)
10297464851774844580…09499746608558510081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.059 × 10⁹⁵(96-digit number)
20594929703549689161…18999493217117020161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
4.118 × 10⁹⁵(96-digit number)
41189859407099378323…37998986434234040321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
8.237 × 10⁹⁵(96-digit number)
82379718814198756647…75997972868468080641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.647 × 10⁹⁶(97-digit number)
16475943762839751329…51995945736936161281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
3.295 × 10⁹⁶(97-digit number)
32951887525679502658…03991891473872322561
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:57,690,921 XPM·at block #6,805,854 · updates every 60s
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