Block #326,010

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/23/2013, 11:44:24 AM · Difficulty 10.1948 · 6,485,917 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
ff34434c7654e32cdcfab64d09b0481cf9d93a9bbf82356d61f5a95aa7987afd

Height

#326,010

Difficulty

10.194760

Transactions

1

Size

1003 B

Version

2

Bits

0a31dbcc

Nonce

1,401

Timestamp

12/23/2013, 11:44:24 AM

Confirmations

6,485,917

Merkle Root

62f516e7ef8a1ceccdd57f99936f89c2b7e75316c7574d42732be261ee14e4e7
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.

1.216 × 10⁹⁴(95-digit number)
12169905083557366907…84671435016874101761
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
1.216 × 10⁹⁴(95-digit number)
12169905083557366907…84671435016874101761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.433 × 10⁹⁴(95-digit number)
24339810167114733815…69342870033748203521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
4.867 × 10⁹⁴(95-digit number)
48679620334229467630…38685740067496407041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
9.735 × 10⁹⁴(95-digit number)
97359240668458935261…77371480134992814081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.947 × 10⁹⁵(96-digit number)
19471848133691787052…54742960269985628161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
3.894 × 10⁹⁵(96-digit number)
38943696267383574104…09485920539971256321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
7.788 × 10⁹⁵(96-digit number)
77887392534767148209…18971841079942512641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.557 × 10⁹⁶(97-digit number)
15577478506953429641…37943682159885025281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
3.115 × 10⁹⁶(97-digit number)
31154957013906859283…75887364319770050561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
6.230 × 10⁹⁶(97-digit number)
62309914027813718567…51774728639540101121
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:57,739,517 XPM·at block #6,811,926 · updates every 60s
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