Block #322,027

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 12/20/2013, 4:51:01 PM · Difficulty 10.1989 · 6,490,830 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
bffb7897622631b4df4eb1694ed21a42373e685facbdd0743d360e7ff22178fa

Height

#322,027

Difficulty

10.198904

Transactions

6

Size

2.19 KB

Version

2

Bits

0a32eb5b

Nonce

35,912

Timestamp

12/20/2013, 4:51:01 PM

Confirmations

6,490,830

Merkle Root

21fc0499648d2dc035a71a3357725258a5e22b1acca05451f30f6ed68d7fecc1
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.

1.091 × 10¹⁰⁰(101-digit number)
10917461902775774068…34925183275726385121
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
1.091 × 10¹⁰⁰(101-digit number)
10917461902775774068…34925183275726385121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.183 × 10¹⁰⁰(101-digit number)
21834923805551548137…69850366551452770241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
4.366 × 10¹⁰⁰(101-digit number)
43669847611103096274…39700733102905540481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
8.733 × 10¹⁰⁰(101-digit number)
87339695222206192549…79401466205811080961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.746 × 10¹⁰¹(102-digit number)
17467939044441238509…58802932411622161921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
3.493 × 10¹⁰¹(102-digit number)
34935878088882477019…17605864823244323841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
6.987 × 10¹⁰¹(102-digit number)
69871756177764954039…35211729646488647681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.397 × 10¹⁰²(103-digit number)
13974351235552990807…70423459292977295361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.794 × 10¹⁰²(103-digit number)
27948702471105981615…40846918585954590721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
5.589 × 10¹⁰²(103-digit number)
55897404942211963231…81693837171909181441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
1.117 × 10¹⁰³(104-digit number)
11179480988442392646…63387674343818362881
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:57,746,892 XPM·at block #6,812,856 · updates every 60s
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