Block #398,373

1CCLength 11★★★☆☆

Cunningham Chain of the First Kind · Discovered 2/10/2014, 4:35:41 PM · Difficulty 10.4243 · 6,410,196 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
d5a954349e9ae261f04cf118fafcfbd9d1af75e8ea16d9463c6a47f30337f119

Height

#398,373

Difficulty

10.424341

Transactions

6

Size

1.86 KB

Version

2

Bits

0a6ca199

Nonce

122,400

Timestamp

2/10/2014, 4:35:41 PM

Confirmations

6,410,196

Merkle Root

642256ac4cbfb861c15d6532f348bd22371e2accf22f084c5b67c54353a327f6
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.

5.552 × 10⁹⁹(100-digit number)
55522531697356166841…49825402907857217339
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
5.552 × 10⁹⁹(100-digit number)
55522531697356166841…49825402907857217339
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
1.110 × 10¹⁰⁰(101-digit number)
11104506339471233368…99650805815714434679
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
2.220 × 10¹⁰⁰(101-digit number)
22209012678942466736…99301611631428869359
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
4.441 × 10¹⁰⁰(101-digit number)
44418025357884933473…98603223262857738719
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
8.883 × 10¹⁰⁰(101-digit number)
88836050715769866946…97206446525715477439
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
1.776 × 10¹⁰¹(102-digit number)
17767210143153973389…94412893051430954879
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
3.553 × 10¹⁰¹(102-digit number)
35534420286307946778…88825786102861909759
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
7.106 × 10¹⁰¹(102-digit number)
71068840572615893557…77651572205723819519
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
1.421 × 10¹⁰²(103-digit number)
14213768114523178711…55303144411447639039
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
2.842 × 10¹⁰²(103-digit number)
28427536229046357422…10606288822895278079
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
11
2^10 × origin − 1
5.685 × 10¹⁰²(103-digit number)
56855072458092714845…21212577645790556159
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 11 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
RareChain length 11

Approximately 1 in 1,000 blocks. Noteworthy discoveries.

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:57,712,607 XPM·at block #6,808,568 · updates every 60s
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