Block #327,115

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/24/2013, 7:56:38 AM · Difficulty 10.1800 · 6,497,644 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
3a2f4a27a0a70f5f57a3acb01a4a9cec7b5af3e1074c96293fa5d13206cb01b6

Height

#327,115

Difficulty

10.180043

Transactions

1

Size

1.05 KB

Version

2

Bits

0a2e1754

Nonce

153,069

Timestamp

12/24/2013, 7:56:38 AM

Confirmations

6,497,644

Merkle Root

32ea27abed7299f9f911372fe7718265bbdff21a58a7804d693b3d0602095e1f
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.

2.611 × 10¹⁰¹(102-digit number)
26114935601609006460…75305769864644101761
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
2.611 × 10¹⁰¹(102-digit number)
26114935601609006460…75305769864644101761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
5.222 × 10¹⁰¹(102-digit number)
52229871203218012920…50611539729288203521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.044 × 10¹⁰²(103-digit number)
10445974240643602584…01223079458576407041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.089 × 10¹⁰²(103-digit number)
20891948481287205168…02446158917152814081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
4.178 × 10¹⁰²(103-digit number)
41783896962574410336…04892317834305628161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
8.356 × 10¹⁰²(103-digit number)
83567793925148820673…09784635668611256321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.671 × 10¹⁰³(104-digit number)
16713558785029764134…19569271337222512641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
3.342 × 10¹⁰³(104-digit number)
33427117570059528269…39138542674445025281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
6.685 × 10¹⁰³(104-digit number)
66854235140119056538…78277085348890050561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.337 × 10¹⁰⁴(105-digit number)
13370847028023811307…56554170697780101121
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:57,842,144 XPM·at block #6,824,758 · updates every 60s
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