Block #166,087

1CCLength 10★★☆☆☆

Cunningham Chain of the First Kind · Discovered 9/15/2013, 5:07:43 PM · Difficulty 9.8670 · 6,646,135 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
af04fcb32a7f870fe374d8a245f768ad243503cf1204f7181154de0d5e8f8b1d

Height

#166,087

Difficulty

9.866976

Transactions

18

Size

5.97 KB

Version

2

Bits

09ddf225

Nonce

76,453

Timestamp

9/15/2013, 5:07:43 PM

Confirmations

6,646,135

Merkle Root

3c60a577c8731baeb0ca91639d0195c22a7e0e9fc8e06bacab5cc47aeb3b7766
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.

1.635 × 10⁹²(93-digit number)
16359829676852307427…76963964826064463039
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
1.635 × 10⁹²(93-digit number)
16359829676852307427…76963964826064463039
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
3.271 × 10⁹²(93-digit number)
32719659353704614854…53927929652128926079
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
6.543 × 10⁹²(93-digit number)
65439318707409229709…07855859304257852159
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
1.308 × 10⁹³(94-digit number)
13087863741481845941…15711718608515704319
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
2.617 × 10⁹³(94-digit number)
26175727482963691883…31423437217031408639
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
5.235 × 10⁹³(94-digit number)
52351454965927383767…62846874434062817279
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
1.047 × 10⁹⁴(95-digit number)
10470290993185476753…25693748868125634559
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
2.094 × 10⁹⁴(95-digit number)
20940581986370953506…51387497736251269119
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
4.188 × 10⁹⁴(95-digit number)
41881163972741907013…02774995472502538239
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
8.376 × 10⁹⁴(95-digit number)
83762327945483814027…05549990945005076479
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 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
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 1CC formula:

1CC: p₁ (first prime), p₂ = 2p₁ + 1, p₃ = 2p₂ + 1, …
Circulating Supply:57,741,791 XPM·at block #6,812,221 · updates every 60s
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