Block #44,056

2CCLength 8★☆☆☆☆

Cunningham Chain of the Second Kind · Discovered 7/14/2013, 10:36:52 PM · Difficulty 8.6964 · 6,747,770 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
72700752c4fea98002afea86532ca49c3e0bac52b06b70edcf5dc75c95294de8

Height

#44,056

Difficulty

8.696445

Transactions

1

Size

197 B

Version

2

Bits

08b24a3a

Nonce

119

Timestamp

7/14/2013, 10:36:52 PM

Confirmations

6,747,770

Merkle Root

45b249493d9ebee429eb0bd0e4f19a09a9589064e04e3a180602807e246d7c56
Transactions (1)
1 in → 1 out13.2000 XPM109 B
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.

2.140 × 10⁹⁰(91-digit number)
21408724545774363427…60611042179468734101
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
2.140 × 10⁹⁰(91-digit number)
21408724545774363427…60611042179468734101
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
4.281 × 10⁹⁰(91-digit number)
42817449091548726854…21222084358937468201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
8.563 × 10⁹⁰(91-digit number)
85634898183097453709…42444168717874936401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.712 × 10⁹¹(92-digit number)
17126979636619490741…84888337435749872801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
3.425 × 10⁹¹(92-digit number)
34253959273238981483…69776674871499745601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
6.850 × 10⁹¹(92-digit number)
68507918546477962967…39553349742999491201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.370 × 10⁹²(93-digit number)
13701583709295592593…79106699485998982401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.740 × 10⁹²(93-digit number)
27403167418591185187…58213398971997964801
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 8 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
CommonChain length 8

Found in most blocks. The baseline for Primecoin's proof-of-work.

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:57,578,557 XPM·at block #6,791,825 · updates every 60s
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