Home/Chain Registry/Block #3,503,913

Block #3,503,913

2CCLength 10ā˜…ā˜…ā˜†ā˜†ā˜†

Cunningham Chain of the Second Kind Ā· Discovered 1/7/2020, 1:16:52 PM Ā· Difficulty 10.9308 Ā· 3,337,119 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
82fbd96e60e79485084a813de9d6d04e4addaa973ae668223801a70904709b4d

Difficulty

10.930841

Transactions

3

Size

847 B

Version

2

Bits

0aee4b97

Nonce

853,839,549

Timestamp

1/7/2020, 1:16:52 PM

Confirmations

3,337,119

Merkle Root

d29587630dfdec0c81159d2300df02d181d5c9edbec57c381dac50c2afa2f239
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.

1.270 Ɨ 10⁹⁵(96-digit number)
12707318358917273642…20320506488374835200
Discovered Prime Numbers
p_k = 2^k Ɨ 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
1.270 Ɨ 10⁹⁵(96-digit number)
12707318358917273642…20320506488374835201
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2āˆ’1 →
2
2^1 Ɨ origin + 1
2.541 Ɨ 10⁹⁵(96-digit number)
25414636717834547284…40641012976749670401
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2āˆ’1 →
3
2^2 Ɨ origin + 1
5.082 Ɨ 10⁹⁵(96-digit number)
50829273435669094569…81282025953499340801
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2āˆ’1 →
4
2^3 Ɨ origin + 1
1.016 Ɨ 10⁹⁶(97-digit number)
10165854687133818913…62564051906998681601
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2āˆ’1 →
5
2^4 Ɨ origin + 1
2.033 Ɨ 10⁹⁶(97-digit number)
20331709374267637827…25128103813997363201
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2āˆ’1 →
6
2^5 Ɨ origin + 1
4.066 Ɨ 10⁹⁶(97-digit number)
40663418748535275655…50256207627994726401
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2āˆ’1 →
7
2^6 Ɨ origin + 1
8.132 Ɨ 10⁹⁶(97-digit number)
81326837497070551310…00512415255989452801
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2āˆ’1 →
8
2^7 Ɨ origin + 1
1.626 Ɨ 10⁹⁷(98-digit number)
16265367499414110262…01024830511978905601
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2āˆ’1 →
9
2^8 Ɨ origin + 1
3.253 Ɨ 10⁹⁷(98-digit number)
32530734998828220524…02049661023957811201
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2āˆ’1 →
10
2^9 Ɨ origin + 1
6.506 Ɨ 10⁹⁷(98-digit number)
65061469997656441048…04099322047915622401
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 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 →
ā˜…ā˜…ā˜†ā˜†ā˜†
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 Ɨ 3 Ɨ 5 Ɨ 7 Ɨ …), 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 Ɨ Primorial (2Ā·3Ā·5Ā·7Ā·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), pā‚‚ = 2p₁ āˆ’ 1, pā‚ƒ = 2pā‚‚ āˆ’ 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 3503913

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 82fbd96e60e79485084a813de9d6d04e4addaa973ae668223801a70904709b4d

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 #3,503,913 on Chainz ↗
Circulating Supply:57,972,615 XPMĀ·at block #6,841,031 Ā· updates every 60s
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