Block #3,460,253

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 12/3/2019, 10:30:04 PM · Difficulty 10.9787 · 3,381,495 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
2e282d2eac694b969dc18fbde5214d983177080d1b8862d58976a2b266048e4b

Height

#3,460,253

Difficulty

10.978728

Transactions

2

Size

10.10 KB

Version

2

Bits

0afa8de9

Nonce

1,050,452,505

Timestamp

12/3/2019, 10:30:04 PM

Confirmations

3,381,495

Merkle Root

dd593748b0efbe4d074f84f7fef51185ceef30da3513517abd12fd1525620c03
Transactions (2)
1 in → 1 out8.3900 XPM109 B
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.

1.848 × 10⁹²(93-digit number)
18483833179752247769…78315024356277315761
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
1.848 × 10⁹²(93-digit number)
18483833179752247769…78315024356277315761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
3.696 × 10⁹²(93-digit number)
36967666359504495538…56630048712554631521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
7.393 × 10⁹²(93-digit number)
73935332719008991077…13260097425109263041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.478 × 10⁹³(94-digit number)
14787066543801798215…26520194850218526081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.957 × 10⁹³(94-digit number)
29574133087603596430…53040389700437052161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
5.914 × 10⁹³(94-digit number)
59148266175207192861…06080779400874104321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.182 × 10⁹⁴(95-digit number)
11829653235041438572…12161558801748208641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.365 × 10⁹⁴(95-digit number)
23659306470082877144…24323117603496417281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
4.731 × 10⁹⁴(95-digit number)
47318612940165754289…48646235206992834561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
9.463 × 10⁹⁴(95-digit number)
94637225880331508578…97292470413985669121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
1.892 × 10⁹⁵(96-digit number)
18927445176066301715…94584940827971338241
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:57,978,369 XPM·at block #6,841,747 · updates every 60s
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