Block #2,679,677

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 5/27/2018, 4:30:39 AM · Difficulty 11.6931 · 4,154,168 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
a648b58edd6a9fb207ca463282994b53daa3006729302d12c3f0623fea8fdc50

Height

#2,679,677

Difficulty

11.693105

Transactions

4

Size

2.59 KB

Version

2

Bits

0bb16f58

Nonce

852,513,408

Timestamp

5/27/2018, 4:30:39 AM

Confirmations

4,154,168

Merkle Root

db420d1a64a8e512b57c11e0da56911cbbd67e6e0ac7e3b8bc6cce4e55bbf375
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.

1.222 × 10⁹⁴(95-digit number)
12224981894219699447…79876894953125091921
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
1.222 × 10⁹⁴(95-digit number)
12224981894219699447…79876894953125091921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.444 × 10⁹⁴(95-digit number)
24449963788439398894…59753789906250183841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
4.889 × 10⁹⁴(95-digit number)
48899927576878797789…19507579812500367681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
9.779 × 10⁹⁴(95-digit number)
97799855153757595578…39015159625000735361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.955 × 10⁹⁵(96-digit number)
19559971030751519115…78030319250001470721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
3.911 × 10⁹⁵(96-digit number)
39119942061503038231…56060638500002941441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
7.823 × 10⁹⁵(96-digit number)
78239884123006076462…12121277000005882881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.564 × 10⁹⁶(97-digit number)
15647976824601215292…24242554000011765761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
3.129 × 10⁹⁶(97-digit number)
31295953649202430584…48485108000023531521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
6.259 × 10⁹⁶(97-digit number)
62591907298404861169…96970216000047063041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
1.251 × 10⁹⁷(98-digit number)
12518381459680972233…93940432000094126081
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 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
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 2CC formula:

2CC: p₁ (first prime), p₂ = 2p₁ − 1, p₃ = 2p₂ − 1, …
Circulating Supply:57,914,990 XPM·at block #6,833,844 · updates every 60s
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