Block #384,465

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 2/1/2014, 3:34:32 AM · Difficulty 10.4003 · 6,425,089 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
0ac72693fbf4543753ab0962e796ae505f69e0096c51543c4eadbfd6da0e7167

Height

#384,465

Difficulty

10.400314

Transactions

4

Size

1.95 KB

Version

2

Bits

0a667b02

Nonce

184,106

Timestamp

2/1/2014, 3:34:32 AM

Confirmations

6,425,089

Merkle Root

33233f9385e74efeb7041e9a3273ef36d0bc513f720c01a25c62b09e2d4bd070
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.

1.660 × 10⁹⁴(95-digit number)
16600129907235129581…75581599444408250401
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
1.660 × 10⁹⁴(95-digit number)
16600129907235129581…75581599444408250401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
3.320 × 10⁹⁴(95-digit number)
33200259814470259162…51163198888816500801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
6.640 × 10⁹⁴(95-digit number)
66400519628940518325…02326397777633001601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.328 × 10⁹⁵(96-digit number)
13280103925788103665…04652795555266003201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.656 × 10⁹⁵(96-digit number)
26560207851576207330…09305591110532006401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
5.312 × 10⁹⁵(96-digit number)
53120415703152414660…18611182221064012801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.062 × 10⁹⁶(97-digit number)
10624083140630482932…37222364442128025601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.124 × 10⁹⁶(97-digit number)
21248166281260965864…74444728884256051201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
4.249 × 10⁹⁶(97-digit number)
42496332562521931728…48889457768512102401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
8.499 × 10⁹⁶(97-digit number)
84992665125043863456…97778915537024204801
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:57,720,506 XPM·at block #6,809,553 · updates every 60s
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