Block #200,327

1CCLength 9★☆☆☆☆

Cunningham Chain of the First Kind · Discovered 10/8/2013, 10:47:32 PM · Difficulty 9.8894 · 6,596,574 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
7e19eeafd837d8cfaae75a203bc0f819ba4006cf3ac24bd6ec68ae8ff91fcaf3

Height

#200,327

Difficulty

9.889360

Transactions

8

Size

2.58 KB

Version

2

Bits

09e3ad19

Nonce

130,948

Timestamp

10/8/2013, 10:47:32 PM

Confirmations

6,596,574

Merkle Root

d84445b33b281fd7f0dca89d468e146c67ad8c629736abbe8b3eb36689f75814
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.

1.057 × 10⁹⁰(91-digit number)
10572014807704132721…77041883507269129999
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
1.057 × 10⁹⁰(91-digit number)
10572014807704132721…77041883507269129999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
2.114 × 10⁹⁰(91-digit number)
21144029615408265443…54083767014538259999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
4.228 × 10⁹⁰(91-digit number)
42288059230816530886…08167534029076519999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
8.457 × 10⁹⁰(91-digit number)
84576118461633061773…16335068058153039999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
1.691 × 10⁹¹(92-digit number)
16915223692326612354…32670136116306079999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
3.383 × 10⁹¹(92-digit number)
33830447384653224709…65340272232612159999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
6.766 × 10⁹¹(92-digit number)
67660894769306449419…30680544465224319999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
1.353 × 10⁹²(93-digit number)
13532178953861289883…61361088930448639999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
2.706 × 10⁹²(93-digit number)
27064357907722579767…22722177860897279999
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 9 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 9

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:57,619,228 XPM·at block #6,796,900 · updates every 60s
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