Block #2,234,970

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 8/3/2017, 10:02:41 AM · Difficulty 10.9456 · 4,604,974 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
35e83027eebbe56f0eabed66b65754f221f2817e97fb3e3d5f8684bed1076136

Height

#2,234,970

Difficulty

10.945592

Transactions

3

Size

1.65 KB

Version

2

Bits

0af2124e

Nonce

2,113,729,582

Timestamp

8/3/2017, 10:02:41 AM

Confirmations

4,604,974

Merkle Root

1570df5fa4f0312fa29766f0e99a5d50a080326acfce994869af374ab899b4b7
Transactions (3)
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.

3.851 × 10⁹⁵(96-digit number)
38518586918749285286…68287300332403573761
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
3.851 × 10⁹⁵(96-digit number)
38518586918749285286…68287300332403573761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
7.703 × 10⁹⁵(96-digit number)
77037173837498570573…36574600664807147521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.540 × 10⁹⁶(97-digit number)
15407434767499714114…73149201329614295041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
3.081 × 10⁹⁶(97-digit number)
30814869534999428229…46298402659228590081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
6.162 × 10⁹⁶(97-digit number)
61629739069998856458…92596805318457180161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.232 × 10⁹⁷(98-digit number)
12325947813999771291…85193610636914360321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.465 × 10⁹⁷(98-digit number)
24651895627999542583…70387221273828720641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
4.930 × 10⁹⁷(98-digit number)
49303791255999085166…40774442547657441281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
9.860 × 10⁹⁷(98-digit number)
98607582511998170333…81548885095314882561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.972 × 10⁹⁸(99-digit number)
19721516502399634066…63097770190629765121
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:57,963,852 XPM·at block #6,839,943 · updates every 60s
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