Block #1,224,510

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 9/6/2015, 11:43:59 AM · Difficulty 10.7393 · 5,600,214 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
6d88c95e591e62e00da091affdd546e8df103b2d6458cff3f42040cf18ec79d8

Height

#1,224,510

Difficulty

10.739285

Transactions

12

Size

4.26 KB

Version

2

Bits

0abd41c2

Nonce

53,158

Timestamp

9/6/2015, 11:43:59 AM

Confirmations

5,600,214

Merkle Root

e0d7c1fd264f40e3c6ec3d7538649f8e426df4de815251f8269ca31f4733123a
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.

5.168 × 10¹⁰²(103-digit number)
51685413324675040767…10300455099839235601
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
5.168 × 10¹⁰²(103-digit number)
51685413324675040767…10300455099839235601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.033 × 10¹⁰³(104-digit number)
10337082664935008153…20600910199678471201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.067 × 10¹⁰³(104-digit number)
20674165329870016307…41201820399356942401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
4.134 × 10¹⁰³(104-digit number)
41348330659740032614…82403640798713884801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
8.269 × 10¹⁰³(104-digit number)
82696661319480065228…64807281597427769601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.653 × 10¹⁰⁴(105-digit number)
16539332263896013045…29614563194855539201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
3.307 × 10¹⁰⁴(105-digit number)
33078664527792026091…59229126389711078401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
6.615 × 10¹⁰⁴(105-digit number)
66157329055584052182…18458252779422156801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.323 × 10¹⁰⁵(106-digit number)
13231465811116810436…36916505558844313601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.646 × 10¹⁰⁵(106-digit number)
26462931622233620873…73833011117688627201
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:57,841,859 XPM·at block #6,824,723 · updates every 60s
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