Block #2,956,759

1CCLength 11★★★☆☆

Cunningham Chain of the First Kind · Discovered 12/8/2018, 4:30:13 AM · Difficulty 11.3750 · 3,885,852 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
5a80b23ffdf86c4672374d4137a54e55dc56e42c6497206bd1709f249c11039f

Height

#2,956,759

Difficulty

11.375036

Transactions

20

Size

6.19 KB

Version

2

Bits

0b600260

Nonce

848,402,918

Timestamp

12/8/2018, 4:30:13 AM

Confirmations

3,885,852

Merkle Root

450095deb181f1bd129c343593956b28b3b0272b6760696063b8f1dc28a1ea2f
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.

8.988 × 10⁹³(94-digit number)
89883259770930076585…64682110647272032779
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
8.988 × 10⁹³(94-digit number)
89883259770930076585…64682110647272032779
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
1.797 × 10⁹⁴(95-digit number)
17976651954186015317…29364221294544065559
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
3.595 × 10⁹⁴(95-digit number)
35953303908372030634…58728442589088131119
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
7.190 × 10⁹⁴(95-digit number)
71906607816744061268…17456885178176262239
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
1.438 × 10⁹⁵(96-digit number)
14381321563348812253…34913770356352524479
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
2.876 × 10⁹⁵(96-digit number)
28762643126697624507…69827540712705048959
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
5.752 × 10⁹⁵(96-digit number)
57525286253395249014…39655081425410097919
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
1.150 × 10⁹⁶(97-digit number)
11505057250679049802…79310162850820195839
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
2.301 × 10⁹⁶(97-digit number)
23010114501358099605…58620325701640391679
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
4.602 × 10⁹⁶(97-digit number)
46020229002716199211…17240651403280783359
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
11
2^10 × origin − 1
9.204 × 10⁹⁶(97-digit number)
92040458005432398423…34481302806561566719
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:57,985,318 XPM·at block #6,842,610 · updates every 60s
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