Block #437,351

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 3/10/2014, 5:58:31 AM · Difficulty 10.3581 · 6,377,037 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
eb2a95d9c4ed5ac633c5dd3a80f89229982481955c1a6b5a5dd2a80b8b052a12

Height

#437,351

Difficulty

10.358071

Transactions

5

Size

1.22 KB

Version

2

Bits

0a5baa8c

Nonce

95,139

Timestamp

3/10/2014, 5:58:31 AM

Confirmations

6,377,037

Merkle Root

25ff8d42e7b801084390b66d04ee14ee44c79dd1265bd5343884c96c13098902
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.

8.854 × 10⁹³(94-digit number)
88541676302533147627…42769517927707056641
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
8.854 × 10⁹³(94-digit number)
88541676302533147627…42769517927707056641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.770 × 10⁹⁴(95-digit number)
17708335260506629525…85539035855414113281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
3.541 × 10⁹⁴(95-digit number)
35416670521013259051…71078071710828226561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
7.083 × 10⁹⁴(95-digit number)
70833341042026518102…42156143421656453121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.416 × 10⁹⁵(96-digit number)
14166668208405303620…84312286843312906241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.833 × 10⁹⁵(96-digit number)
28333336416810607240…68624573686625812481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
5.666 × 10⁹⁵(96-digit number)
56666672833621214481…37249147373251624961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.133 × 10⁹⁶(97-digit number)
11333334566724242896…74498294746503249921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.266 × 10⁹⁶(97-digit number)
22666669133448485792…48996589493006499841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
4.533 × 10⁹⁶(97-digit number)
45333338266896971585…97993178986012999681
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:57,759,165 XPM·at block #6,814,387 · updates every 60s
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