Block #352,186

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/10/2014, 4:38:41 AM · Difficulty 10.3039 · 6,452,869 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
16772c15cb705a1e2d2f871cb7859528e877bb480f73d270a5cc235d6bd5bdea

Height

#352,186

Difficulty

10.303854

Transactions

4

Size

2.48 KB

Version

2

Bits

0a4dc959

Nonce

911,424

Timestamp

1/10/2014, 4:38:41 AM

Confirmations

6,452,869

Merkle Root

ceaeb1ec9a3136bbb85c0730deae4ea24bf90f07f7255fc986f49e11fc3ff809
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.

3.590 × 10⁹³(94-digit number)
35901705357464970971…24192434495254213421
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
3.590 × 10⁹³(94-digit number)
35901705357464970971…24192434495254213421
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
7.180 × 10⁹³(94-digit number)
71803410714929941942…48384868990508426841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.436 × 10⁹⁴(95-digit number)
14360682142985988388…96769737981016853681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.872 × 10⁹⁴(95-digit number)
28721364285971976777…93539475962033707361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
5.744 × 10⁹⁴(95-digit number)
57442728571943953554…87078951924067414721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.148 × 10⁹⁵(96-digit number)
11488545714388790710…74157903848134829441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.297 × 10⁹⁵(96-digit number)
22977091428777581421…48315807696269658881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
4.595 × 10⁹⁵(96-digit number)
45954182857555162843…96631615392539317761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
9.190 × 10⁹⁵(96-digit number)
91908365715110325687…93263230785078635521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.838 × 10⁹⁶(97-digit number)
18381673143022065137…86526461570157271041
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:57,684,505 XPM·at block #6,805,054 · updates every 60s
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