Block #338,764

1CCLength 10★★☆☆☆

Cunningham Chain of the First Kind · Discovered 1/1/2014, 3:46:58 PM · Difficulty 10.1245 · 6,458,053 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
72e5b7bf0840380a7d7c66a8d1142d2a3fd33c0fde373790a0b3772966475423

Height

#338,764

Difficulty

10.124494

Transactions

2

Size

860 B

Version

2

Bits

0a1fded0

Nonce

351,577

Timestamp

1/1/2014, 3:46:58 PM

Confirmations

6,458,053

Merkle Root

0958eae00d9378914c59fa7bcb6d4033aa0b157e3189f2c4bf007160321b1f16
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.

9.697 × 10⁹⁸(99-digit number)
96975894303461181880…30579601007977309039
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
9.697 × 10⁹⁸(99-digit number)
96975894303461181880…30579601007977309039
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
1.939 × 10⁹⁹(100-digit number)
19395178860692236376…61159202015954618079
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
3.879 × 10⁹⁹(100-digit number)
38790357721384472752…22318404031909236159
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
7.758 × 10⁹⁹(100-digit number)
77580715442768945504…44636808063818472319
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
1.551 × 10¹⁰⁰(101-digit number)
15516143088553789100…89273616127636944639
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
3.103 × 10¹⁰⁰(101-digit number)
31032286177107578201…78547232255273889279
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
6.206 × 10¹⁰⁰(101-digit number)
62064572354215156403…57094464510547778559
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
1.241 × 10¹⁰¹(102-digit number)
12412914470843031280…14188929021095557119
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
2.482 × 10¹⁰¹(102-digit number)
24825828941686062561…28377858042191114239
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
4.965 × 10¹⁰¹(102-digit number)
49651657883372125122…56755716084382228479
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 First 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 1CC formula:

1CC: p₁ (first prime), p₂ = 2p₁ + 1, p₃ = 2p₂ + 1, …
Circulating Supply:57,618,545 XPM·at block #6,796,816 · updates every 60s
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