Block #456,164

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 3/23/2014, 1:00:30 AM · Difficulty 10.4167 · 6,354,910 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
7647d4b4008a6f563313622c8ae7281a1775104dbcf13aabda6f285c205c4552

Height

#456,164

Difficulty

10.416732

Transactions

1

Size

1.01 KB

Version

2

Bits

0a6aaeec

Nonce

12,114

Timestamp

3/23/2014, 1:00:30 AM

Confirmations

6,354,910

Merkle Root

f45824373658c7b9bd6c2daae1762236d4116fac0fc5a76eafc9a1740b519d76
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.

8.702 × 10⁹³(94-digit number)
87025133865964618276…84937847878455898081
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
8.702 × 10⁹³(94-digit number)
87025133865964618276…84937847878455898081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.740 × 10⁹⁴(95-digit number)
17405026773192923655…69875695756911796161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
3.481 × 10⁹⁴(95-digit number)
34810053546385847310…39751391513823592321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
6.962 × 10⁹⁴(95-digit number)
69620107092771694620…79502783027647184641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.392 × 10⁹⁵(96-digit number)
13924021418554338924…59005566055294369281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.784 × 10⁹⁵(96-digit number)
27848042837108677848…18011132110588738561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
5.569 × 10⁹⁵(96-digit number)
55696085674217355696…36022264221177477121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.113 × 10⁹⁶(97-digit number)
11139217134843471139…72044528442354954241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.227 × 10⁹⁶(97-digit number)
22278434269686942278…44089056884709908481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
4.455 × 10⁹⁶(97-digit number)
44556868539373884557…88178113769419816961
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:57,732,697 XPM·at block #6,811,073 · updates every 60s
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