Home/Chain Registry/Block #11,960

Block #11,960

2CCLength 7★☆☆☆☆

Cunningham Chain of the Second Kind · Discovered 7/11/2013, 8:17:11 AM · Difficulty 7.7416 · 6,797,970 confirmations

2CC

Cunningham Chain of the Second Kind

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

Block Header

Block Hash

2eaa6b94f29cbcaa3186cb5abbd38f104afa724249be699ffbfb8e1c5d91865a

View on Chainz ↗

Height

#11,960

Difficulty

7.741601

Transactions

Size

209 B

Version

Bits

07bdd989

Nonce

165

Timestamp

7/11/2013, 8:17:11 AM

Confirmations

6,797,970

Merkle Root

931889aa5bde5baeb238e18aea0d625525742cc98e2386e451f9d3650aca3694

Transactions (1)

Coinbase931889aa5bde5b…f9d3650aca3694

1 in → 1 out16.6600 XPM108 B

AP35U7Z1…HpLUxvbK

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.

9.578 × 10¹²¹(122-digit number)

95782750357970839595…53959777581529564160

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.

origin + 1

9.578 × 10¹²¹(122-digit number)

95782750357970839595…53959777581529564161

Verify on FactorDB ↗Wolfram Alpha ↗

×2−1 →

2^1 × origin + 1

1.915 × 10¹²²(123-digit number)

19156550071594167919…07919555163059128321

Verify on FactorDB ↗Wolfram Alpha ↗

×2−1 →

2^2 × origin + 1

3.831 × 10¹²²(123-digit number)

38313100143188335838…15839110326118256641

Verify on FactorDB ↗Wolfram Alpha ↗

×2−1 →

2^3 × origin + 1

7.662 × 10¹²²(123-digit number)

76626200286376671676…31678220652236513281

Verify on FactorDB ↗Wolfram Alpha ↗

×2−1 →

2^4 × origin + 1

1.532 × 10¹²³(124-digit number)

15325240057275334335…63356441304473026561

Verify on FactorDB ↗Wolfram Alpha ↗

×2−1 →

2^5 × origin + 1

3.065 × 10¹²³(124-digit number)

30650480114550668670…26712882608946053121

Verify on FactorDB ↗Wolfram Alpha ↗

×2−1 →

2^6 × origin + 1

6.130 × 10¹²³(124-digit number)

61300960229101337341…53425765217892106241

Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 7 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 7

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 11960

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 2eaa6b94f29cbcaa3186cb5abbd38f104afa724249be699ffbfb8e1c5d91865a

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 #11,960 on Chainz ↗

Block #11,960

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