Block #326,206

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/23/2013, 3:09:29 PM · Difficulty 10.1935 · 6,483,518 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
05ead0235f95933e593bdf49294190f51be91ccdb64bd558ee7b0c3170f81b94

Height

#326,206

Difficulty

10.193457

Transactions

8

Size

3.16 KB

Version

2

Bits

0a318663

Nonce

33,258

Timestamp

12/23/2013, 3:09:29 PM

Confirmations

6,483,518

Merkle Root

b38439a826a7f479733b561d247f1a9375c749bb0cf215d64897508b670706e6
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.

2.057 × 10¹⁰²(103-digit number)
20571799060502350409…86176620814753064961
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
2.057 × 10¹⁰²(103-digit number)
20571799060502350409…86176620814753064961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
4.114 × 10¹⁰²(103-digit number)
41143598121004700818…72353241629506129921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
8.228 × 10¹⁰²(103-digit number)
82287196242009401636…44706483259012259841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.645 × 10¹⁰³(104-digit number)
16457439248401880327…89412966518024519681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
3.291 × 10¹⁰³(104-digit number)
32914878496803760654…78825933036049039361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
6.582 × 10¹⁰³(104-digit number)
65829756993607521308…57651866072098078721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.316 × 10¹⁰⁴(105-digit number)
13165951398721504261…15303732144196157441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.633 × 10¹⁰⁴(105-digit number)
26331902797443008523…30607464288392314881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
5.266 × 10¹⁰⁴(105-digit number)
52663805594886017047…61214928576784629761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.053 × 10¹⁰⁵(106-digit number)
10532761118977203409…22429857153569259521
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 10 consecutive prime numbers forming a Cunningham Chain of the Second 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
UncommonChain length 10

Roughly 1 in 100 blocks. Solid but expected in a healthy network.

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 2CC formula:

2CC: p₁ (first prime), p₂ = 2p₁ − 1, p₃ = 2p₂ − 1, …
Circulating Supply:57,721,873 XPM·at block #6,809,723 · updates every 60s
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