Block #408,001

1CCLength 10ā˜…ā˜…ā˜†ā˜†ā˜†

Cunningham Chain of the First Kind Ā· Discovered 2/17/2014, 8:55:33 AM Ā· Difficulty 10.4293 Ā· 6,406,948 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
6167363e3460ed3b6498badc38fb87eff99867776c3db909a3b6e9a60c4a188b

Height

#408,001

Difficulty

10.429288

Transactions

2

Size

1.49 KB

Version

2

Bits

0a6de5cc

Nonce

171,289

Timestamp

2/17/2014, 8:55:33 AM

Confirmations

6,406,948

Mined by

Merkle Root

7e38abe6ad409f2578fd7c73e761e0c2864148f197cb7d37413557289f23609c
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.

1.117 Ɨ 10⁹⁵(96-digit number)
11171878980196603929…60102236449106086399
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
1.117 Ɨ 10⁹⁵(96-digit number)
11171878980196603929…60102236449106086399
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2+1 →
2
2^1 Ɨ origin āˆ’ 1
2.234 Ɨ 10⁹⁵(96-digit number)
22343757960393207858…20204472898212172799
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2+1 →
3
2^2 Ɨ origin āˆ’ 1
4.468 Ɨ 10⁹⁵(96-digit number)
44687515920786415717…40408945796424345599
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2+1 →
4
2^3 Ɨ origin āˆ’ 1
8.937 Ɨ 10⁹⁵(96-digit number)
89375031841572831434…80817891592848691199
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2+1 →
5
2^4 Ɨ origin āˆ’ 1
1.787 Ɨ 10⁹⁶(97-digit number)
17875006368314566286…61635783185697382399
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2+1 →
6
2^5 Ɨ origin āˆ’ 1
3.575 Ɨ 10⁹⁶(97-digit number)
35750012736629132573…23271566371394764799
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2+1 →
7
2^6 Ɨ origin āˆ’ 1
7.150 Ɨ 10⁹⁶(97-digit number)
71500025473258265147…46543132742789529599
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2+1 →
8
2^7 Ɨ origin āˆ’ 1
1.430 Ɨ 10⁹⁷(98-digit number)
14300005094651653029…93086265485579059199
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2+1 →
9
2^8 Ɨ origin āˆ’ 1
2.860 Ɨ 10⁹⁷(98-digit number)
28600010189303306059…86172530971158118399
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2+1 →
10
2^9 Ɨ origin āˆ’ 1
5.720 Ɨ 10⁹⁷(98-digit number)
57200020378606612118…72345061942316236799
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:57,763,689 XPMĀ·at block #6,814,948 Ā· updates every 60s
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