Block #3,014,993

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 1/18/2019, 2:37:54 PM · Difficulty 11.1757 · 3,818,985 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
78f03548c37e1aa96ce97e7cfeda2a394ba7c2aa7902d6933346e3bba227ffbe

Height

#3,014,993

Difficulty

11.175666

Transactions

3

Size

1.07 KB

Version

2

Bits

0b2cf878

Nonce

225,872,153

Timestamp

1/18/2019, 2:37:54 PM

Confirmations

3,818,985

Merkle Root

dbb0ee5ebd39a69c9245df5d719ebec9245160f27c749ff0528e40ed8d4a0519
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.

1.804 × 10⁹⁴(95-digit number)
18042438500171825237…80774790955108423681
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
1.804 × 10⁹⁴(95-digit number)
18042438500171825237…80774790955108423681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
3.608 × 10⁹⁴(95-digit number)
36084877000343650474…61549581910216847361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
7.216 × 10⁹⁴(95-digit number)
72169754000687300948…23099163820433694721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.443 × 10⁹⁵(96-digit number)
14433950800137460189…46198327640867389441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.886 × 10⁹⁵(96-digit number)
28867901600274920379…92396655281734778881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
5.773 × 10⁹⁵(96-digit number)
57735803200549840758…84793310563469557761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.154 × 10⁹⁶(97-digit number)
11547160640109968151…69586621126939115521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.309 × 10⁹⁶(97-digit number)
23094321280219936303…39173242253878231041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
4.618 × 10⁹⁶(97-digit number)
46188642560439872607…78346484507756462081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
9.237 × 10⁹⁶(97-digit number)
92377285120879745214…56692969015512924161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
1.847 × 10⁹⁷(98-digit number)
18475457024175949042…13385938031025848321
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:57,916,048 XPM·at block #6,833,977 · updates every 60s
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