Block #3,039,767

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 2/5/2019, 10:06:14 AM · Difficulty 11.0205 · 3,799,352 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
ddc0bc08a5a0952a7162db79ba18744865c19a8969f784306799388c1d88969a

Height

#3,039,767

Difficulty

11.020547

Transactions

2

Size

2.58 KB

Version

2

Bits

0b05428d

Nonce

1,206,082,857

Timestamp

2/5/2019, 10:06:14 AM

Confirmations

3,799,352

Merkle Root

02b6b1f9a614bc29d58bbf6cb1490bac55a0e52bec8eaad0ff2c4bfd7d20595d
Transactions (2)
1 in → 1 out8.2500 XPM110 B
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.

2.113 × 10⁹⁵(96-digit number)
21132627006821616507…23482126407616401921
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
2.113 × 10⁹⁵(96-digit number)
21132627006821616507…23482126407616401921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
4.226 × 10⁹⁵(96-digit number)
42265254013643233015…46964252815232803841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
8.453 × 10⁹⁵(96-digit number)
84530508027286466030…93928505630465607681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.690 × 10⁹⁶(97-digit number)
16906101605457293206…87857011260931215361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
3.381 × 10⁹⁶(97-digit number)
33812203210914586412…75714022521862430721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
6.762 × 10⁹⁶(97-digit number)
67624406421829172824…51428045043724861441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.352 × 10⁹⁷(98-digit number)
13524881284365834564…02856090087449722881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.704 × 10⁹⁷(98-digit number)
27049762568731669129…05712180174899445761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
5.409 × 10⁹⁷(98-digit number)
54099525137463338259…11424360349798891521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.081 × 10⁹⁸(99-digit number)
10819905027492667651…22848720699597783041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
2.163 × 10⁹⁸(99-digit number)
21639810054985335303…45697441399195566081
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:57,957,227 XPM·at block #6,839,118 · updates every 60s
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