1. #6,807,8221CC11 primes

    Cunningham 1st · ⛏️ coinsforall.io

Block #314,212

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/15/2013, 8:41:27 PM · Difficulty 10.0497 · 6,493,611 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
1ea72d8744304490e4280fa437f850ce1ac1807f698ea9b5d90ff38aa7a18568

Height

#314,212

Difficulty

10.049670

Transactions

4

Size

875 B

Version

2

Bits

0a0cb729

Nonce

27,627

Timestamp

12/15/2013, 8:41:27 PM

Confirmations

6,493,611

Merkle Root

7891e0f6f1cb6f7d2caf36d2664d2601aba814a1717086c54da417d0ce31e605
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.

1.940 × 10⁹³(94-digit number)
19404384176948673075…98481294324039358081
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
1.940 × 10⁹³(94-digit number)
19404384176948673075…98481294324039358081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
3.880 × 10⁹³(94-digit number)
38808768353897346150…96962588648078716161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
7.761 × 10⁹³(94-digit number)
77617536707794692300…93925177296157432321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.552 × 10⁹⁴(95-digit number)
15523507341558938460…87850354592314864641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
3.104 × 10⁹⁴(95-digit number)
31047014683117876920…75700709184629729281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
6.209 × 10⁹⁴(95-digit number)
62094029366235753840…51401418369259458561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.241 × 10⁹⁵(96-digit number)
12418805873247150768…02802836738518917121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.483 × 10⁹⁵(96-digit number)
24837611746494301536…05605673477037834241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
4.967 × 10⁹⁵(96-digit number)
49675223492988603072…11211346954075668481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
9.935 × 10⁹⁵(96-digit number)
99350446985977206144…22422693908151336961
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:57,706,620 XPM·at block #6,807,822 · updates every 60s
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