Home/Chain Registry/Block #674,264

Block #674,264

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 8/12/2014, 3:40:49 AM · Difficulty 10.9653 · 6,152,913 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
8d29d798d3cb6d13690acbf7e0c83e1faacf5b1031f5e9c3565cf0fd4724057b

Height

#674,264

Difficulty

10.965266

Transactions

7

Size

2.47 KB

Version

2

Bits

0af71ba6

Nonce

36,377,347

Timestamp

8/12/2014, 3:40:49 AM

Confirmations

6,152,913

Merkle Root

97bc17183b1b63239a7fbd6a50eed3dc3ed4f29792e3e1f097d3962de5c13cec
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.

3.114 × 10⁹⁷(98-digit number)
31140804881437931219…99160971664957784000
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
3.114 × 10⁹⁷(98-digit number)
31140804881437931219…99160971664957784001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
6.228 × 10⁹⁷(98-digit number)
62281609762875862439…98321943329915568001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.245 × 10⁹⁸(99-digit number)
12456321952575172487…96643886659831136001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.491 × 10⁹⁸(99-digit number)
24912643905150344975…93287773319662272001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
4.982 × 10⁹⁸(99-digit number)
49825287810300689951…86575546639324544001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
9.965 × 10⁹⁸(99-digit number)
99650575620601379903…73151093278649088001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.993 × 10⁹⁹(100-digit number)
19930115124120275980…46302186557298176001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
3.986 × 10⁹⁹(100-digit number)
39860230248240551961…92604373114596352001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
7.972 × 10⁹⁹(100-digit number)
79720460496481103922…85208746229192704001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.594 × 10¹⁰⁰(101-digit number)
15944092099296220784…70417492458385408001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
3.188 × 10¹⁰⁰(101-digit number)
31888184198592441569…40834984916770816001
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 11 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
RareChain length 11
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 674264

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 8d29d798d3cb6d13690acbf7e0c83e1faacf5b1031f5e9c3565cf0fd4724057b

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 #674,264 on Chainz ↗
Circulating Supply:57,861,513 XPM·at block #6,827,176 · updates every 60s
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