Block #2,046,072

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 3/31/2017, 3:13:43 AM · Difficulty 10.6850 · 4,771,780 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
d90957961a7913b18f0948a596cc3810aa3690707a5832e84ca02e3900e34e9a

Height

#2,046,072

Difficulty

10.685031

Transactions

3

Size

3.82 KB

Version

2

Bits

0aaf5e34

Nonce

713,668,748

Timestamp

3/31/2017, 3:13:43 AM

Confirmations

4,771,780

Merkle Root

7d05fe86e66db32617f1c69296d12f9d5f027331da58cba10bd0f8daffe707be
Transactions (3)
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.

1.053 × 10⁹²(93-digit number)
10536217416683801530…21594698320900413881
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
1.053 × 10⁹²(93-digit number)
10536217416683801530…21594698320900413881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.107 × 10⁹²(93-digit number)
21072434833367603060…43189396641800827761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
4.214 × 10⁹²(93-digit number)
42144869666735206120…86378793283601655521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
8.428 × 10⁹²(93-digit number)
84289739333470412241…72757586567203311041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.685 × 10⁹³(94-digit number)
16857947866694082448…45515173134406622081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
3.371 × 10⁹³(94-digit number)
33715895733388164896…91030346268813244161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
6.743 × 10⁹³(94-digit number)
67431791466776329793…82060692537626488321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.348 × 10⁹⁴(95-digit number)
13486358293355265958…64121385075252976641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.697 × 10⁹⁴(95-digit number)
26972716586710531917…28242770150505953281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
5.394 × 10⁹⁴(95-digit number)
53945433173421063834…56485540301011906561
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 10 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
UncommonChain length 10

Roughly 1 in 100 blocks. Solid but expected in a healthy network.

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:57,786,882 XPM·at block #6,817,851 · updates every 60s
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