Block #323,274

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/21/2013, 1:12:59 PM · Difficulty 10.2036 · 6,502,092 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
cc93e14cfd72c0eafc275d74166124709a0273691bbaeaa72312bcd3641c8370

Height

#323,274

Difficulty

10.203602

Transactions

13

Size

2.85 KB

Version

2

Bits

0a341f3c

Nonce

109,649

Timestamp

12/21/2013, 1:12:59 PM

Confirmations

6,502,092

Merkle Root

4a4cf2e3a1aafb90169231e2043e5867783e5d5427b5596cf5f9df0abc201c01
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.

1.051 × 10¹⁰¹(102-digit number)
10516208677674918267…00828913739684184721
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
1.051 × 10¹⁰¹(102-digit number)
10516208677674918267…00828913739684184721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.103 × 10¹⁰¹(102-digit number)
21032417355349836534…01657827479368369441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
4.206 × 10¹⁰¹(102-digit number)
42064834710699673069…03315654958736738881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
8.412 × 10¹⁰¹(102-digit number)
84129669421399346138…06631309917473477761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.682 × 10¹⁰²(103-digit number)
16825933884279869227…13262619834946955521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
3.365 × 10¹⁰²(103-digit number)
33651867768559738455…26525239669893911041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
6.730 × 10¹⁰²(103-digit number)
67303735537119476910…53050479339787822081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.346 × 10¹⁰³(104-digit number)
13460747107423895382…06100958679575644161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.692 × 10¹⁰³(104-digit number)
26921494214847790764…12201917359151288321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
5.384 × 10¹⁰³(104-digit number)
53842988429695581528…24403834718302576641
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:57,847,024 XPM·at block #6,825,365 · updates every 60s
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