Block #135,462

2CCLength 9★☆☆☆☆

Cunningham Chain of the Second Kind · Discovered 8/26/2013, 3:38:23 PM · Difficulty 9.8105 · 6,670,992 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
1c50a2666c7e23920036a27bc90ff3256e053cdb23db960cbe44807d115df071

Height

#135,462

Difficulty

9.810544

Transactions

11

Size

2.98 KB

Version

2

Bits

09cf7fd3

Nonce

9,110

Timestamp

8/26/2013, 3:38:23 PM

Confirmations

6,670,992

Merkle Root

e7616f00897be5c6eb97e9968852faf94beb9ec76be3770063a3bd3ab42bf9fc
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.

1.132 × 10¹⁰⁰(101-digit number)
11324809576709460615…14944373000647263841
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
1.132 × 10¹⁰⁰(101-digit number)
11324809576709460615…14944373000647263841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.264 × 10¹⁰⁰(101-digit number)
22649619153418921230…29888746001294527681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
4.529 × 10¹⁰⁰(101-digit number)
45299238306837842460…59777492002589055361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
9.059 × 10¹⁰⁰(101-digit number)
90598476613675684920…19554984005178110721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.811 × 10¹⁰¹(102-digit number)
18119695322735136984…39109968010356221441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
3.623 × 10¹⁰¹(102-digit number)
36239390645470273968…78219936020712442881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
7.247 × 10¹⁰¹(102-digit number)
72478781290940547936…56439872041424885761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.449 × 10¹⁰²(103-digit number)
14495756258188109587…12879744082849771521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.899 × 10¹⁰²(103-digit number)
28991512516376219174…25759488165699543041
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:57,695,723 XPM·at block #6,806,453 · updates every 60s
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