Block #3,433,670

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 11/15/2019, 4:09:12 AM · Difficulty 10.9797 · 3,393,334 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
1d26768e1b19a13583899f1e1ca9e83f087b1db0b01e8323fda6a2687d116d06

Height

#3,433,670

Difficulty

10.979742

Transactions

2

Size

542 B

Version

2

Bits

0afad05a

Nonce

624,131,081

Timestamp

11/15/2019, 4:09:12 AM

Confirmations

3,393,334

Merkle Root

b6fc8507324e7c0f307e70197eb122381a96f252d620f063d39a0a440853e07a
Transactions (2)
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.

6.601 × 10⁹⁵(96-digit number)
66017430817422101036…99987156571818595841
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
6.601 × 10⁹⁵(96-digit number)
66017430817422101036…99987156571818595841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.320 × 10⁹⁶(97-digit number)
13203486163484420207…99974313143637191681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.640 × 10⁹⁶(97-digit number)
26406972326968840414…99948626287274383361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
5.281 × 10⁹⁶(97-digit number)
52813944653937680829…99897252574548766721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.056 × 10⁹⁷(98-digit number)
10562788930787536165…99794505149097533441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.112 × 10⁹⁷(98-digit number)
21125577861575072331…99589010298195066881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
4.225 × 10⁹⁷(98-digit number)
42251155723150144663…99178020596390133761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
8.450 × 10⁹⁷(98-digit number)
84502311446300289326…98356041192780267521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.690 × 10⁹⁸(99-digit number)
16900462289260057865…96712082385560535041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
3.380 × 10⁹⁸(99-digit number)
33800924578520115730…93424164771121070081
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:57,860,208 XPM·at block #6,827,003 · updates every 60s
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