Block #273,110

2CCLength 9★☆☆☆☆

Cunningham Chain of the Second Kind · Discovered 11/25/2013, 3:21:22 PM · Difficulty 9.9541 · 6,529,422 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
3e892443258bdec35f3802f1e6fc01795cad958d98db79541e7712c1e2d97e22

Height

#273,110

Difficulty

9.954113

Transactions

8

Size

2.75 KB

Version

2

Bits

09f440bf

Nonce

956

Timestamp

11/25/2013, 3:21:22 PM

Confirmations

6,529,422

Merkle Root

eb1fdf1333f201c69688628748e956b1d46e487a969d72438b3f04d410ed0e79
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.

4.629 × 10¹⁰⁴(105-digit number)
46292309449622800934…13804224767619146241
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
4.629 × 10¹⁰⁴(105-digit number)
46292309449622800934…13804224767619146241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
9.258 × 10¹⁰⁴(105-digit number)
92584618899245601869…27608449535238292481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.851 × 10¹⁰⁵(106-digit number)
18516923779849120373…55216899070476584961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
3.703 × 10¹⁰⁵(106-digit number)
37033847559698240747…10433798140953169921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
7.406 × 10¹⁰⁵(106-digit number)
74067695119396481495…20867596281906339841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.481 × 10¹⁰⁶(107-digit number)
14813539023879296299…41735192563812679681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.962 × 10¹⁰⁶(107-digit number)
29627078047758592598…83470385127625359361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
5.925 × 10¹⁰⁶(107-digit number)
59254156095517185196…66940770255250718721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.185 × 10¹⁰⁷(108-digit number)
11850831219103437039…33881540510501437441
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 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
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 2CC formula:

2CC: p₁ (first prime), p₂ = 2p₁ − 1, p₃ = 2p₂ − 1, …
Circulating Supply:57,664,265 XPM·at block #6,802,531 · updates every 60s
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