Block #1,492,629

1CCLength 10ā˜…ā˜…ā˜†ā˜†ā˜†

Cunningham Chain of the First Kind Ā· Discovered 3/11/2016, 3:07:15 PM Ā· Difficulty 10.6744 Ā· 5,334,269 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
5735e18ff3c01572ec52d7fbbd807117dba7c9e4e8509ec9611e9bfb58bf2869

Height

#1,492,629

Difficulty

10.674431

Transactions

2

Size

1.04 KB

Version

2

Bits

0aaca784

Nonce

20,099,636

Timestamp

3/11/2016, 3:07:15 PM

Confirmations

5,334,269

Mined by

Merkle Root

1299b24aeba5f3c7fd8ef83952dae6e649e992f79eef79434cf594468406517c
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.

1.428 Ɨ 10⁹⁵(96-digit number)
14282337351049849000…86912072119770307199
Discovered Prime Numbers
p_k = 2^k Ɨ origin āˆ’ 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 āˆ’ 1
1.428 Ɨ 10⁹⁵(96-digit number)
14282337351049849000…86912072119770307199
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2+1 →
2
2^1 Ɨ origin āˆ’ 1
2.856 Ɨ 10⁹⁵(96-digit number)
28564674702099698001…73824144239540614399
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2+1 →
3
2^2 Ɨ origin āˆ’ 1
5.712 Ɨ 10⁹⁵(96-digit number)
57129349404199396003…47648288479081228799
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2+1 →
4
2^3 Ɨ origin āˆ’ 1
1.142 Ɨ 10⁹⁶(97-digit number)
11425869880839879200…95296576958162457599
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2+1 →
5
2^4 Ɨ origin āˆ’ 1
2.285 Ɨ 10⁹⁶(97-digit number)
22851739761679758401…90593153916324915199
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2+1 →
6
2^5 Ɨ origin āˆ’ 1
4.570 Ɨ 10⁹⁶(97-digit number)
45703479523359516803…81186307832649830399
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2+1 →
7
2^6 Ɨ origin āˆ’ 1
9.140 Ɨ 10⁹⁶(97-digit number)
91406959046719033606…62372615665299660799
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2+1 →
8
2^7 Ɨ origin āˆ’ 1
1.828 Ɨ 10⁹⁷(98-digit number)
18281391809343806721…24745231330599321599
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2+1 →
9
2^8 Ɨ origin āˆ’ 1
3.656 Ɨ 10⁹⁷(98-digit number)
36562783618687613442…49490462661198643199
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2+1 →
10
2^9 Ɨ origin āˆ’ 1
7.312 Ɨ 10⁹⁷(98-digit number)
73125567237375226885…98980925322397286399
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 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.

ā˜…ā˜…ā˜†ā˜†ā˜†
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 Ɨ 3 Ɨ 5 Ɨ 7 Ɨ …), 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 Ɨ Primorial (2Ā·3Ā·5Ā·7Ā·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), pā‚‚ = 2p₁ + 1, pā‚ƒ = 2pā‚‚ + 1, …
Circulating Supply:57,859,350 XPMĀ·at block #6,826,897 Ā· updates every 60s
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