Home/Chain Registry/Block #376,937

Block #376,937

1CCLength 10★★☆☆☆

Cunningham Chain of the First Kind · Discovered 1/26/2014, 6:14:16 PM · Difficulty 10.4250 · 6,423,330 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
81f976c3cebaca775d3b8adbe6d56f2def07c28cf71a0f21e0b2f511a3450127

Height

#376,937

Difficulty

10.424995

Transactions

7

Size

14.40 KB

Version

2

Bits

0a6ccc78

Nonce

83,886,361

Timestamp

1/26/2014, 6:14:16 PM

Confirmations

6,423,330

Merkle Root

b24d81dea49254ebd61d80831cbd8f3ec9577896f9a53b5b0a91a5f8f9f61066
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.

4.582 × 10¹⁰⁴(105-digit number)
45829733824536878649…83691920553863901440
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
4.582 × 10¹⁰⁴(105-digit number)
45829733824536878649…83691920553863901439
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
9.165 × 10¹⁰⁴(105-digit number)
91659467649073757298…67383841107727802879
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
1.833 × 10¹⁰⁵(106-digit number)
18331893529814751459…34767682215455605759
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
3.666 × 10¹⁰⁵(106-digit number)
36663787059629502919…69535364430911211519
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
7.332 × 10¹⁰⁵(106-digit number)
73327574119259005838…39070728861822423039
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
1.466 × 10¹⁰⁶(107-digit number)
14665514823851801167…78141457723644846079
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
2.933 × 10¹⁰⁶(107-digit number)
29331029647703602335…56282915447289692159
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
5.866 × 10¹⁰⁶(107-digit number)
58662059295407204671…12565830894579384319
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
1.173 × 10¹⁰⁷(108-digit number)
11732411859081440934…25131661789158768639
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
2.346 × 10¹⁰⁷(108-digit number)
23464823718162881868…50263323578317537279
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.

View full Prime Chain Discovery page →
★★☆☆☆
Rarity
UncommonChain length 10
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 376937

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 81f976c3cebaca775d3b8adbe6d56f2def07c28cf71a0f21e0b2f511a3450127

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 #376,937 on Chainz ↗
Circulating Supply:57,646,193 XPM·at block #6,800,266 · updates every 60s
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