Block #352,795

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/10/2014, 1:50:18 PM · Difficulty 10.3117 · 6,439,121 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
cfda73d5b3159b2f298ccdf21045534b5d6a44b45a33136e89cab5b7c89472d3

Height

#352,795

Difficulty

10.311733

Transactions

6

Size

12.01 KB

Version

2

Bits

0a4fcdc0

Nonce

189,947

Timestamp

1/10/2014, 1:50:18 PM

Confirmations

6,439,121

Merkle Root

cdd49668ff279a334ef11c4a9b23b6db7d976863e01343bdc5787496b61973e2
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.

2.463 × 10⁹⁶(97-digit number)
24637002923131928663…57490360118446231041
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
2.463 × 10⁹⁶(97-digit number)
24637002923131928663…57490360118446231041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
4.927 × 10⁹⁶(97-digit number)
49274005846263857326…14980720236892462081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
9.854 × 10⁹⁶(97-digit number)
98548011692527714652…29961440473784924161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.970 × 10⁹⁷(98-digit number)
19709602338505542930…59922880947569848321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
3.941 × 10⁹⁷(98-digit number)
39419204677011085860…19845761895139696641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
7.883 × 10⁹⁷(98-digit number)
78838409354022171721…39691523790279393281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.576 × 10⁹⁸(99-digit number)
15767681870804434344…79383047580558786561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
3.153 × 10⁹⁸(99-digit number)
31535363741608868688…58766095161117573121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
6.307 × 10⁹⁸(99-digit number)
63070727483217737377…17532190322235146241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.261 × 10⁹⁹(100-digit number)
12614145496643547475…35064380644470292481
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:57,579,281 XPM·at block #6,791,915 · updates every 60s
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