Block #2,870,465

1CCLength 11★★★☆☆

Cunningham Chain of the First Kind · Discovered 10/7/2018, 1:21:31 AM · Difficulty 11.6648 · 3,956,833 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
5842d50b1d985ab16999c60ba0f7f7232714adec05e88ca2390f48f090516702

Height

#2,870,465

Difficulty

11.664803

Transactions

3

Size

582 B

Version

2

Bits

0baa3084

Nonce

398,460,904

Timestamp

10/7/2018, 1:21:31 AM

Confirmations

3,956,833

Merkle Root

fb1b7a2d252684d51122b19ba7baf974c3a079d102a1534c68e7958e44732346
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.

2.654 × 10⁹²(93-digit number)
26540317433773762365…85612894975978834079
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
2.654 × 10⁹²(93-digit number)
26540317433773762365…85612894975978834079
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
5.308 × 10⁹²(93-digit number)
53080634867547524731…71225789951957668159
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
1.061 × 10⁹³(94-digit number)
10616126973509504946…42451579903915336319
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
2.123 × 10⁹³(94-digit number)
21232253947019009892…84903159807830672639
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
4.246 × 10⁹³(94-digit number)
42464507894038019785…69806319615661345279
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
8.492 × 10⁹³(94-digit number)
84929015788076039570…39612639231322690559
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
1.698 × 10⁹⁴(95-digit number)
16985803157615207914…79225278462645381119
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
3.397 × 10⁹⁴(95-digit number)
33971606315230415828…58450556925290762239
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
6.794 × 10⁹⁴(95-digit number)
67943212630460831656…16901113850581524479
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
1.358 × 10⁹⁵(96-digit number)
13588642526092166331…33802227701163048959
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
11
2^10 × origin − 1
2.717 × 10⁹⁵(96-digit number)
27177285052184332662…67604455402326097919
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 First 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 1CC formula:

1CC: p₁ (first prime), p₂ = 2p₁ + 1, p₃ = 2p₂ + 1, …
Circulating Supply:57,862,494 XPM·at block #6,827,297 · updates every 60s
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