Block #135,555

1CCLength 11★★★☆☆

Cunningham Chain of the First Kind · Discovered 8/26/2013, 4:54:36 PM · Difficulty 9.8112 · 6,659,985 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
2c8ebf00e95487a0d83b42beca656413fda3f7a285a836bcf0ab4f6c82e29185

Height

#135,555

Difficulty

9.811234

Transactions

2

Size

425 B

Version

2

Bits

09cfad0a

Nonce

258,624

Timestamp

8/26/2013, 4:54:36 PM

Confirmations

6,659,985

Merkle Root

34c1e6aac0e1b18a7aa3b08408c059809437e3f3a4ef0c1936bb8d376b4bf103
Transactions (2)
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.

5.133 × 10⁹¹(92-digit number)
51337972317285729613…24382076339607043839
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
5.133 × 10⁹¹(92-digit number)
51337972317285729613…24382076339607043839
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
1.026 × 10⁹²(93-digit number)
10267594463457145922…48764152679214087679
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
2.053 × 10⁹²(93-digit number)
20535188926914291845…97528305358428175359
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
4.107 × 10⁹²(93-digit number)
41070377853828583690…95056610716856350719
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
8.214 × 10⁹²(93-digit number)
82140755707657167381…90113221433712701439
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
1.642 × 10⁹³(94-digit number)
16428151141531433476…80226442867425402879
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
3.285 × 10⁹³(94-digit number)
32856302283062866952…60452885734850805759
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
6.571 × 10⁹³(94-digit number)
65712604566125733905…20905771469701611519
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
1.314 × 10⁹⁴(95-digit number)
13142520913225146781…41811542939403223039
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
2.628 × 10⁹⁴(95-digit number)
26285041826450293562…83623085878806446079
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
11
2^10 × origin − 1
5.257 × 10⁹⁴(95-digit number)
52570083652900587124…67246171757612892159
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 11 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
RareChain length 11

Approximately 1 in 1,000 blocks. Noteworthy discoveries.

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:57,608,385 XPM·at block #6,795,539 · updates every 60s
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