Block #356,119

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/12/2014, 1:46:05 PM · Difficulty 10.3719 · 6,450,753 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
8df77531a050dabdbdaa899bbe03cfaa4b1e0e195b62dae9b4eee1efcbeead16

Height

#356,119

Difficulty

10.371911

Transactions

11

Size

4.39 KB

Version

2

Bits

0a5f358f

Nonce

15,947

Timestamp

1/12/2014, 1:46:05 PM

Confirmations

6,450,753

Merkle Root

60181490d9e7f6fd9ac2d0db330f53fae3578aca9ed4bd5898c62d035c16ccef
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.

4.829 × 10¹⁰⁰(101-digit number)
48297622940205428619…34607830103765376001
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
4.829 × 10¹⁰⁰(101-digit number)
48297622940205428619…34607830103765376001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
9.659 × 10¹⁰⁰(101-digit number)
96595245880410857238…69215660207530752001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.931 × 10¹⁰¹(102-digit number)
19319049176082171447…38431320415061504001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
3.863 × 10¹⁰¹(102-digit number)
38638098352164342895…76862640830123008001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
7.727 × 10¹⁰¹(102-digit number)
77276196704328685790…53725281660246016001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.545 × 10¹⁰²(103-digit number)
15455239340865737158…07450563320492032001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
3.091 × 10¹⁰²(103-digit number)
30910478681731474316…14901126640984064001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
6.182 × 10¹⁰²(103-digit number)
61820957363462948632…29802253281968128001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.236 × 10¹⁰³(104-digit number)
12364191472692589726…59604506563936256001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.472 × 10¹⁰³(104-digit number)
24728382945385179452…19209013127872512001
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:57,699,083 XPM·at block #6,806,871 · updates every 60s
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