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Home/Chain Registry/Block #1,371,822

Block #1,371,822

2CCLength 11β˜…β˜…β˜…β˜†β˜†

Cunningham Chain of the Second Kind Β· Discovered 12/16/2015, 6:42:50 PM Β· Difficulty 10.8102 Β· 5,470,597 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
f2df258b63343ca79cd76001c662373fe0fea28e5a8988f683500f2a090a6382
View on Chainz β†—

Difficulty

10.810199

Transactions

1

Size

200 B

Version

2

Bits

0acf6935

Nonce

45,976,973

Timestamp

12/16/2015, 6:42:50 PM

Confirmations

5,470,597

Merkle Root

8af7cfa7f93945cdc44ea55e04f438fce0ba95a5df3f91cd2a9c4689ff42a25a
Transactions (1)
Coinbase8af7cfa7f93945…9c4689ff42a25a
1 in β†’ 1 out8.5400 XPM109 B
AKDo8Tv1…CCEtQRg9
Prime Chain Origin

This is the prime chain origin stored in the block header. It is a composite number (not prime itself) β€” it equals the first prime in the chain multiplied by a primorial. The origin anchors the entire chain to this specific block.

3.806 Γ— 10⁹⁢(97-digit number)
38067730809427960952…25623011645678584320
Discovered Prime Numbers
p_k = 2^k Γ— 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
3.806 Γ— 10⁹⁢(97-digit number)
38067730809427960952…25623011645678584321
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
2
2^1 Γ— origin + 1
7.613 Γ— 10⁹⁢(97-digit number)
76135461618855921904…51246023291357168641
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
3
2^2 Γ— origin + 1
1.522 Γ— 10⁹⁷(98-digit number)
15227092323771184380…02492046582714337281
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
4
2^3 Γ— origin + 1
3.045 Γ— 10⁹⁷(98-digit number)
30454184647542368761…04984093165428674561
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
5
2^4 Γ— origin + 1
6.090 Γ— 10⁹⁷(98-digit number)
60908369295084737523…09968186330857349121
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
6
2^5 Γ— origin + 1
1.218 Γ— 10⁹⁸(99-digit number)
12181673859016947504…19936372661714698241
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
7
2^6 Γ— origin + 1
2.436 Γ— 10⁹⁸(99-digit number)
24363347718033895009…39872745323429396481
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
8
2^7 Γ— origin + 1
4.872 Γ— 10⁹⁸(99-digit number)
48726695436067790018…79745490646858792961
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
9
2^8 Γ— origin + 1
9.745 Γ— 10⁹⁸(99-digit number)
97453390872135580037…59490981293717585921
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
10
2^9 Γ— origin + 1
1.949 Γ— 10⁹⁹(100-digit number)
19490678174427116007…18981962587435171841
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
11
2^10 Γ— origin + 1
3.898 Γ— 10⁹⁹(100-digit number)
38981356348854232015…37963925174870343681
Verify on FactorDB β†—Wolfram Alpha β†—

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 β€” the large number shown above β€” 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 β†’
β˜…β˜…β˜…β˜†β˜†
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 Γ— 3 Γ— 5 Γ— 7 Γ— …), the result is the first prime in the chain. The origin is deliberately divisible by this primorial β€” that divisibility is part of the proof.

Prime Chain Origin = First Prime Γ— Primorial (2Β·3Β·5Β·7Β·11·…)
Source: Primecoin prime.cpp β€” CheckPrimeProofOfWork()

This is why the origin has many small prime factors β€” those factors are the primorial divisor. The chain then extends from the first prime using the 2CC formula:

2CC: p₁ (first prime), pβ‚‚ = 2p₁ βˆ’ 1, p₃ = 2pβ‚‚ βˆ’ 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 1371822

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 f2df258b63343ca79cd76001c662373fe0fea28e5a8988f683500f2a090a6382

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 β†’ Debug Window β†’ 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 #1,371,822 on Chainz β†—
Circulating Supply:57,983,766 XPMΒ·at block #6,842,418 Β· updates every 60s
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