Block #2,479,125

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 1/18/2018, 5:41:37 PM · Difficulty 10.9659 · 4,364,915 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
f351e387a1868df3f1a2c473c82893295a2676f6609b04d7fc24b366f7deb797

Height

#2,479,125

Difficulty

10.965863

Transactions

5

Size

2.24 KB

Version

2

Bits

0af742ca

Nonce

1,957,303,876

Timestamp

1/18/2018, 5:41:37 PM

Confirmations

4,364,915

Merkle Root

316a807ec61548ac405830019e06b8fb7c4293f41fef060a6ae650eb8ba1f6a4
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.

8.702 × 10⁹⁴(95-digit number)
87020390833374892710…85401892796987514881
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
8.702 × 10⁹⁴(95-digit number)
87020390833374892710…85401892796987514881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.740 × 10⁹⁵(96-digit number)
17404078166674978542…70803785593975029761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
3.480 × 10⁹⁵(96-digit number)
34808156333349957084…41607571187950059521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
6.961 × 10⁹⁵(96-digit number)
69616312666699914168…83215142375900119041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.392 × 10⁹⁶(97-digit number)
13923262533339982833…66430284751800238081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.784 × 10⁹⁶(97-digit number)
27846525066679965667…32860569503600476161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
5.569 × 10⁹⁶(97-digit number)
55693050133359931334…65721139007200952321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.113 × 10⁹⁷(98-digit number)
11138610026671986266…31442278014401904641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.227 × 10⁹⁷(98-digit number)
22277220053343972533…62884556028803809281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
4.455 × 10⁹⁷(98-digit number)
44554440106687945067…25769112057607618561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
8.910 × 10⁹⁷(98-digit number)
89108880213375890135…51538224115215237121
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 11 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
RareChain length 11

Approximately 1 in 1,000 blocks. Noteworthy discoveries.

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:57,996,689 XPM·at block #6,844,039 · updates every 60s
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