Block #83,324

1CCLength 9★☆☆☆☆

Cunningham Chain of the First Kind · Discovered 7/26/2013, 2:01:24 AM · Difficulty 9.2676 · 6,707,922 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
8d7e65784e2ef19c7a8a559a6aafcba24d4d754e9fc6334b579324171fb77b19

Height

#83,324

Difficulty

9.267596

Transactions

2

Size

425 B

Version

2

Bits

09448133

Nonce

90,110

Timestamp

7/26/2013, 2:01:24 AM

Confirmations

6,707,922

Merkle Root

fd042905998e574d7acc00c5f0fbb78e1ad5a56e2e9098691d5d58d239e9cb51
Transactions (2)
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.

2.134 × 10⁹³(94-digit number)
21343930579598282839…96217084331815938749
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
2.134 × 10⁹³(94-digit number)
21343930579598282839…96217084331815938749
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
4.268 × 10⁹³(94-digit number)
42687861159196565679…92434168663631877499
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
8.537 × 10⁹³(94-digit number)
85375722318393131358…84868337327263754999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
1.707 × 10⁹⁴(95-digit number)
17075144463678626271…69736674654527509999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
3.415 × 10⁹⁴(95-digit number)
34150288927357252543…39473349309055019999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
6.830 × 10⁹⁴(95-digit number)
68300577854714505087…78946698618110039999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
1.366 × 10⁹⁵(96-digit number)
13660115570942901017…57893397236220079999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
2.732 × 10⁹⁵(96-digit number)
27320231141885802034…15786794472440159999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
5.464 × 10⁹⁵(96-digit number)
54640462283771604069…31573588944880319999
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:57,573,905 XPM·at block #6,791,245 · updates every 60s
xpmprime.info is a work in progress. If you enjoy using this service you can support this project with a Primecoin donation.