Block #38,859

1CCLength 8★☆☆☆☆

Cunningham Chain of the First Kind · Discovered 7/14/2013, 12:37:49 PM · Difficulty 8.2439 · 6,787,284 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
4a74afc97187ce4afc1eafd9a92007c3764a6c30534879cf596d9ecb79563ce2

Height

#38,859

Difficulty

8.243881

Transactions

3

Size

629 B

Version

2

Bits

083e6efc

Nonce

369

Timestamp

7/14/2013, 12:37:49 PM

Confirmations

6,787,284

Merkle Root

5dd9241c587de946e8259d9c81335ed251acba7e36ee9588b99a5cf91957ea14
Transactions (3)
1 in → 1 out14.7100 XPM109 B
1 in → 1 out15.7600 XPM158 B
2 in → 1 out31.4300 XPM274 B
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.

8.915 × 10⁸⁹(90-digit number)
89155867148044512313…29236562505357697279
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
8.915 × 10⁸⁹(90-digit number)
89155867148044512313…29236562505357697279
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
1.783 × 10⁹⁰(91-digit number)
17831173429608902462…58473125010715394559
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
3.566 × 10⁹⁰(91-digit number)
35662346859217804925…16946250021430789119
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
7.132 × 10⁹⁰(91-digit number)
71324693718435609850…33892500042861578239
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
1.426 × 10⁹¹(92-digit number)
14264938743687121970…67785000085723156479
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
2.852 × 10⁹¹(92-digit number)
28529877487374243940…35570000171446312959
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
5.705 × 10⁹¹(92-digit number)
57059754974748487880…71140000342892625919
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
1.141 × 10⁹²(93-digit number)
11411950994949697576…42280000685785251839
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 8 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
CommonChain length 8

Found in most blocks. The baseline for Primecoin's proof-of-work.

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:57,853,269 XPM·at block #6,826,142 · updates every 60s
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