Block #316,050

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/16/2013, 8:34:25 PM · Difficulty 10.1235 · 6,496,506 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
4d934d92f2a62bb083ec23a9dbc3facb9e282162cb1d43ca2a2985eb5f0a7628

Height

#316,050

Difficulty

10.123496

Transactions

11

Size

2.52 KB

Version

2

Bits

0a1f9d6f

Nonce

129,275

Timestamp

12/16/2013, 8:34:25 PM

Confirmations

6,496,506

Merkle Root

20873032249d75989264c211557efda4f57128aa934c8055ee1e73accc6191cf
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.

4.973 × 10¹⁰¹(102-digit number)
49732134589274914627…36574590524371671041
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
4.973 × 10¹⁰¹(102-digit number)
49732134589274914627…36574590524371671041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
9.946 × 10¹⁰¹(102-digit number)
99464269178549829254…73149181048743342081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.989 × 10¹⁰²(103-digit number)
19892853835709965850…46298362097486684161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
3.978 × 10¹⁰²(103-digit number)
39785707671419931701…92596724194973368321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
7.957 × 10¹⁰²(103-digit number)
79571415342839863403…85193448389946736641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.591 × 10¹⁰³(104-digit number)
15914283068567972680…70386896779893473281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
3.182 × 10¹⁰³(104-digit number)
31828566137135945361…40773793559786946561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
6.365 × 10¹⁰³(104-digit number)
63657132274271890722…81547587119573893121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.273 × 10¹⁰⁴(105-digit number)
12731426454854378144…63095174239147786241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.546 × 10¹⁰⁴(105-digit number)
25462852909708756289…26190348478295572481
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:57,744,481 XPM·at block #6,812,555 · updates every 60s
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