Block #1,111,766

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 6/17/2015, 1:46:28 AM · Difficulty 10.8885 · 5,696,913 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
72afdfb63b30e93a3f276f1d33a3ccfa36f4d1293c0bdab0e00dba6ae98ca7a1

Height

#1,111,766

Difficulty

10.888477

Transactions

3

Size

27.30 KB

Version

2

Bits

0ae3733a

Nonce

7,626,401

Timestamp

6/17/2015, 1:46:28 AM

Confirmations

5,696,913

Merkle Root

d76ba0b00e32014b912ccead390690cf1f9b3469e51ba184aba5454604aff5e0
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.

1.891 × 10⁹⁵(96-digit number)
18912098033137596894…31690537521973137921
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
1.891 × 10⁹⁵(96-digit number)
18912098033137596894…31690537521973137921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
3.782 × 10⁹⁵(96-digit number)
37824196066275193788…63381075043946275841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
7.564 × 10⁹⁵(96-digit number)
75648392132550387576…26762150087892551681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.512 × 10⁹⁶(97-digit number)
15129678426510077515…53524300175785103361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
3.025 × 10⁹⁶(97-digit number)
30259356853020155030…07048600351570206721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
6.051 × 10⁹⁶(97-digit number)
60518713706040310060…14097200703140413441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.210 × 10⁹⁷(98-digit number)
12103742741208062012…28194401406280826881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.420 × 10⁹⁷(98-digit number)
24207485482416124024…56388802812561653761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
4.841 × 10⁹⁷(98-digit number)
48414970964832248048…12777605625123307521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
9.682 × 10⁹⁷(98-digit number)
96829941929664496097…25555211250246615041
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:57,713,478 XPM·at block #6,808,678 · updates every 60s
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