Home/Chain Registry/Block #79,512

Block #79,512

2CCLength 9★☆☆☆☆

Cunningham Chain of the Second Kind · Discovered 7/23/2013, 12:53:15 PM · Difficulty 9.2466 · 6,712,659 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
cacfd372f8bbeb5c5c753de4a9ccfe1ed9b606d0cbbfcf9d00e0862dc990cf7c

Height

#79,512

Difficulty

9.246574

Transactions

7

Size

1.97 KB

Version

2

Bits

093f1f81

Nonce

67,452

Timestamp

7/23/2013, 12:53:15 PM

Confirmations

6,712,659

Merkle Root

e637fb5d05df05551644a90fb5b84ef36fbef203749c7f77cad303d16fb81107
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.

1.925 × 10¹⁰⁰(101-digit number)
19259366813704416227…82113235002106691500
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
1.925 × 10¹⁰⁰(101-digit number)
19259366813704416227…82113235002106691501
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
3.851 × 10¹⁰⁰(101-digit number)
38518733627408832454…64226470004213383001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
7.703 × 10¹⁰⁰(101-digit number)
77037467254817664908…28452940008426766001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.540 × 10¹⁰¹(102-digit number)
15407493450963532981…56905880016853532001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
3.081 × 10¹⁰¹(102-digit number)
30814986901927065963…13811760033707064001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
6.162 × 10¹⁰¹(102-digit number)
61629973803854131926…27623520067414128001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.232 × 10¹⁰²(103-digit number)
12325994760770826385…55247040134828256001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.465 × 10¹⁰²(103-digit number)
24651989521541652770…10494080269656512001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
4.930 × 10¹⁰²(103-digit number)
49303979043083305541…20988160539313024001
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 9 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.

View full Prime Chain Discovery page →
★☆☆☆☆
Rarity
CommonChain length 9
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, …
Verify on a Primecoin Node

Anyone running a Primecoin node can independently verify this block using the following RPC commands. Run these from the primecoin-cli command line or via the debug console in the Primecoin wallet.

1. Get block hash by height
getblockhash 79512

Returns the block hash for a given block height. Use this to confirm the hash shown above matches the chain.

2. Get full block data
getblock cacfd372f8bbeb5c5c753de4a9ccfe1ed9b606d0cbbfcf9d00e0862dc990cf7c

Returns the full block header including difficulty, prime chain origin, prime chain type, transaction IDs, and all other fields shown on this page.

How to run these commands: To verify this data independently, open a terminal on your own Primecoin node and run primecoin-cli <command>. Alternatively, open the Primecoin-Qt wallet, go to Help → Debug Window → Console, and type the command directly. The node must be fully synced to this block height for the commands to return results.

Cross-reference on Chainz Explorer

Chainz is an independent Primecoin block explorer. Compare this block's data to verify accuracy.

View Block #79,512 on Chainz ↗
Circulating Supply:57,581,324 XPM·at block #6,792,170 · updates every 60s
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