Block #3,033,923

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 2/1/2019, 7:36:33 AM · Difficulty 11.0329 · 3,806,996 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
b213fa9d27424f47f36f2a0b98a20dcefe6bc0ecb5ac54a2a149b30592730fd8

Height

#3,033,923

Difficulty

11.032864

Transactions

3

Size

766 B

Version

2

Bits

0b0869cd

Nonce

125,391,944

Timestamp

2/1/2019, 7:36:33 AM

Confirmations

3,806,996

Merkle Root

5c75916ec1160f732ecf3922142d1b58e3f5660ad73d5e858b23daa1f1870996
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.

1.056 × 10⁹⁷(98-digit number)
10561645859260034931…25224002432619315201
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
1.056 × 10⁹⁷(98-digit number)
10561645859260034931…25224002432619315201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.112 × 10⁹⁷(98-digit number)
21123291718520069862…50448004865238630401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
4.224 × 10⁹⁷(98-digit number)
42246583437040139724…00896009730477260801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
8.449 × 10⁹⁷(98-digit number)
84493166874080279449…01792019460954521601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.689 × 10⁹⁸(99-digit number)
16898633374816055889…03584038921909043201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
3.379 × 10⁹⁸(99-digit number)
33797266749632111779…07168077843818086401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
6.759 × 10⁹⁸(99-digit number)
67594533499264223559…14336155687636172801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.351 × 10⁹⁹(100-digit number)
13518906699852844711…28672311375272345601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.703 × 10⁹⁹(100-digit number)
27037813399705689423…57344622750544691201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
5.407 × 10⁹⁹(100-digit number)
54075626799411378847…14689245501089382401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
1.081 × 10¹⁰⁰(101-digit number)
10815125359882275769…29378491002178764801
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:57,971,703 XPM·at block #6,840,918 · updates every 60s
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