Home/Chain Registry/Block #275,591

Block #275,591

1CCLength 9★☆☆☆☆

Cunningham Chain of the First Kind · Discovered 11/26/2013, 6:48:49 PM · Difficulty 9.9612 · 6,525,105 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
f52a5e34a4fac5297f411b0a26b28917d8c19fc4ec9f4edab9fa027a07228261

Height

#275,591

Difficulty

9.961176

Transactions

15

Size

49.69 KB

Version

2

Bits

09f60f9e

Nonce

2,002

Timestamp

11/26/2013, 6:48:49 PM

Confirmations

6,525,105

Merkle Root

cd1ec042b9662e99c8695d15cef0093f30b104c4275bcee043a4764afa8411a1
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.

3.345 × 10¹⁰⁴(105-digit number)
33454566693639245902…08429758667050729600
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
3.345 × 10¹⁰⁴(105-digit number)
33454566693639245902…08429758667050729599
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
6.690 × 10¹⁰⁴(105-digit number)
66909133387278491805…16859517334101459199
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
1.338 × 10¹⁰⁵(106-digit number)
13381826677455698361…33719034668202918399
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
2.676 × 10¹⁰⁵(106-digit number)
26763653354911396722…67438069336405836799
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
5.352 × 10¹⁰⁵(106-digit number)
53527306709822793444…34876138672811673599
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
1.070 × 10¹⁰⁶(107-digit number)
10705461341964558688…69752277345623347199
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
2.141 × 10¹⁰⁶(107-digit number)
21410922683929117377…39504554691246694399
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
4.282 × 10¹⁰⁶(107-digit number)
42821845367858234755…79009109382493388799
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
8.564 × 10¹⁰⁶(107-digit number)
85643690735716469511…58018218764986777599
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 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.

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 1CC formula:

1CC: 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 275591

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 f52a5e34a4fac5297f411b0a26b28917d8c19fc4ec9f4edab9fa027a07228261

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 #275,591 on Chainz ↗
Circulating Supply:57,649,633 XPM·at block #6,800,695 · updates every 60s
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