Block #3,054,891

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 2/16/2019, 4:46:04 AM · Difficulty 11.0034 · 3,781,989 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
9d5122ce54411445d93d4115924d134be392a2a60f41b824002c30025d0c5abf

Height

#3,054,891

Difficulty

11.003439

Transactions

2

Size

1019 B

Version

2

Bits

0b00e166

Nonce

867,720,798

Timestamp

2/16/2019, 4:46:04 AM

Confirmations

3,781,989

Merkle Root

dc0de80b0d57b53b1606d8ee4120621779e01411baab12a04bed7a538371e51e
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.

4.411 × 10⁹³(94-digit number)
44115038125787517133…48442641589217865811
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
4.411 × 10⁹³(94-digit number)
44115038125787517133…48442641589217865811
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
8.823 × 10⁹³(94-digit number)
88230076251575034266…96885283178435731621
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.764 × 10⁹⁴(95-digit number)
17646015250315006853…93770566356871463241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
3.529 × 10⁹⁴(95-digit number)
35292030500630013706…87541132713742926481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
7.058 × 10⁹⁴(95-digit number)
70584061001260027413…75082265427485852961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.411 × 10⁹⁵(96-digit number)
14116812200252005482…50164530854971705921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.823 × 10⁹⁵(96-digit number)
28233624400504010965…00329061709943411841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
5.646 × 10⁹⁵(96-digit number)
56467248801008021930…00658123419886823681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.129 × 10⁹⁶(97-digit number)
11293449760201604386…01316246839773647361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.258 × 10⁹⁶(97-digit number)
22586899520403208772…02632493679547294721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
4.517 × 10⁹⁶(97-digit number)
45173799040806417544…05264987359094589441
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:57,939,331 XPM·at block #6,836,879 · updates every 60s
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