Block #41,469

1CCLength 8★☆☆☆☆

Cunningham Chain of the First Kind · Discovered 7/14/2013, 4:42:14 PM · Difficulty 8.5272 · 6,768,252 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
fd105a9c0af16f692f8e9b10dad0acce0d2a8c399fd02f7ac67aa828411ceec2

Height

#41,469

Difficulty

8.527177

Transactions

3

Size

516 B

Version

2

Bits

0886f50e

Nonce

24

Timestamp

7/14/2013, 4:42:14 PM

Confirmations

6,768,252

Merkle Root

afcf647cd92d3dddac840953da82582f0fddb27fc330d37709659416ff15ebd6
Transactions (3)
1 in → 1 out13.7500 XPM109 B
1 in → 1 out15.6100 XPM157 B
1 in → 1 out15.5400 XPM159 B
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.

1.752 × 10⁹⁶(97-digit number)
17521133334721649550…78249161813473012299
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
1.752 × 10⁹⁶(97-digit number)
17521133334721649550…78249161813473012299
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
3.504 × 10⁹⁶(97-digit number)
35042266669443299101…56498323626946024599
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
7.008 × 10⁹⁶(97-digit number)
70084533338886598203…12996647253892049199
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
1.401 × 10⁹⁷(98-digit number)
14016906667777319640…25993294507784098399
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
2.803 × 10⁹⁷(98-digit number)
28033813335554639281…51986589015568196799
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
5.606 × 10⁹⁷(98-digit number)
56067626671109278562…03973178031136393599
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
1.121 × 10⁹⁸(99-digit number)
11213525334221855712…07946356062272787199
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
2.242 × 10⁹⁸(99-digit number)
22427050668443711425…15892712124545574399
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 8 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 8

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:57,721,849 XPM·at block #6,809,720 · updates every 60s
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