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Block #1,231,900

1CCLength 10β˜…β˜…β˜†β˜†β˜†

Cunningham Chain of the First Kind Β· Discovered 9/11/2015, 2:36:29 PM Β· Difficulty 10.7403 Β· 5,606,620 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
7b01a33f4963957c40813cb3bb8481a4cd10990e5ad7508c6d14517ccbb3428e
View on Chainz β†—

Difficulty

10.740325

Transactions

1

Size

200 B

Version

2

Bits

0abd85f4

Nonce

266,396,764

Timestamp

9/11/2015, 2:36:29 PM

Confirmations

5,606,620

Merkle Root

4db70d06d490ce9e9d717e4a5cd5bdebca81ed98baf9d7ac2a292c9e6c32d025
Transactions (1)
Coinbase4db70d06d490ce…292c9e6c32d025
1 in β†’ 1 out8.6600 XPM109 B
AP4eNBDV…N1oRF5z5
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.

2.882 Γ— 10⁹⁢(97-digit number)
28828529340881012500…88111131238650227200
Discovered Prime Numbers
p_k = 2^k Γ— origin βˆ’ 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 βˆ’ 1
2.882 Γ— 10⁹⁢(97-digit number)
28828529340881012500…88111131238650227199
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
2
2^1 Γ— origin βˆ’ 1
5.765 Γ— 10⁹⁢(97-digit number)
57657058681762025001…76222262477300454399
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
3
2^2 Γ— origin βˆ’ 1
1.153 Γ— 10⁹⁷(98-digit number)
11531411736352405000…52444524954600908799
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
4
2^3 Γ— origin βˆ’ 1
2.306 Γ— 10⁹⁷(98-digit number)
23062823472704810000…04889049909201817599
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
5
2^4 Γ— origin βˆ’ 1
4.612 Γ— 10⁹⁷(98-digit number)
46125646945409620001…09778099818403635199
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
6
2^5 Γ— origin βˆ’ 1
9.225 Γ— 10⁹⁷(98-digit number)
92251293890819240002…19556199636807270399
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
7
2^6 Γ— origin βˆ’ 1
1.845 Γ— 10⁹⁸(99-digit number)
18450258778163848000…39112399273614540799
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
8
2^7 Γ— origin βˆ’ 1
3.690 Γ— 10⁹⁸(99-digit number)
36900517556327696000…78224798547229081599
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
9
2^8 Γ— origin βˆ’ 1
7.380 Γ— 10⁹⁸(99-digit number)
73801035112655392001…56449597094458163199
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
10
2^9 Γ— origin βˆ’ 1
1.476 Γ— 10⁹⁹(100-digit number)
14760207022531078400…12899194188916326399
Verify on FactorDB β†—Wolfram Alpha β†—

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 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
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 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 1CC formula:

1CC: p₁ (first prime), pβ‚‚ = 2p₁ + 1, p₃ = 2pβ‚‚ + 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 1231900

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 7b01a33f4963957c40813cb3bb8481a4cd10990e5ad7508c6d14517ccbb3428e

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 #1,231,900 on Chainz β†—
Circulating Supply:57,952,438 XPMΒ·at block #6,838,519 Β· updates every 60s
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