Block #62,217

1CCLength 9★☆☆☆☆

Cunningham Chain of the First Kind · Discovered 7/18/2013, 5:49:55 PM · Difficulty 8.9757 · 6,729,699 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
afc1a8ac1580d39478f6e80b8983a40c2f65429d6664cdb99053c98981d9b11d

Height

#62,217

Difficulty

8.975728

Transactions

6

Size

3.45 KB

Version

2

Bits

08f9c954

Nonce

138

Timestamp

7/18/2013, 5:49:55 PM

Confirmations

6,729,699

Merkle Root

504359e707bb150f05aa18a2ed6e1d5d5d68f4088899e15e941672b19f7b36d7
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.

4.231 × 10¹⁰¹(102-digit number)
42314811732475590388…11102203989120038209
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
4.231 × 10¹⁰¹(102-digit number)
42314811732475590388…11102203989120038209
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
8.462 × 10¹⁰¹(102-digit number)
84629623464951180776…22204407978240076419
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
1.692 × 10¹⁰²(103-digit number)
16925924692990236155…44408815956480152839
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
3.385 × 10¹⁰²(103-digit number)
33851849385980472310…88817631912960305679
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
6.770 × 10¹⁰²(103-digit number)
67703698771960944621…77635263825920611359
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
1.354 × 10¹⁰³(104-digit number)
13540739754392188924…55270527651841222719
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
2.708 × 10¹⁰³(104-digit number)
27081479508784377848…10541055303682445439
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
5.416 × 10¹⁰³(104-digit number)
54162959017568755697…21082110607364890879
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
1.083 × 10¹⁰⁴(105-digit number)
10832591803513751139…42164221214729781759
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:57,579,281 XPM·at block #6,791,915 · updates every 60s
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