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Home/Chain Registry/Block #1,237,115

Block #1,237,115

2CCLength 10β˜…β˜…β˜†β˜†β˜†

Cunningham Chain of the Second Kind Β· Discovered 9/15/2015, 12:02:51 AM Β· Difficulty 10.7568 Β· 5,587,563 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
0885bffae77c0d1aa257d3eff38c8df96aaecbe78e38b976934a5194307f12bc
View on Chainz β†—

Difficulty

10.756847

Transactions

1

Size

200 B

Version

2

Bits

0ac1c0b3

Nonce

1,076,827,872

Timestamp

9/15/2015, 12:02:51 AM

Confirmations

5,587,563

Merkle Root

9e31a57b22b4f096b84e20f5a76d36acb96a0463557c8841b8abc533e4c3fa4c
Transactions (1)
Coinbase9e31a57b22b4f0…abc533e4c3fa4c
1 in β†’ 1 out8.6300 XPM109 B
AKARV63Y…NwFDkp1m
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.

2.504 Γ— 10⁹⁢(97-digit number)
25044945092535933832…06689146168196979200
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
2.504 Γ— 10⁹⁢(97-digit number)
25044945092535933832…06689146168196979201
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
2
2^1 Γ— origin + 1
5.008 Γ— 10⁹⁢(97-digit number)
50089890185071867664…13378292336393958401
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
3
2^2 Γ— origin + 1
1.001 Γ— 10⁹⁷(98-digit number)
10017978037014373532…26756584672787916801
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
4
2^3 Γ— origin + 1
2.003 Γ— 10⁹⁷(98-digit number)
20035956074028747065…53513169345575833601
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
5
2^4 Γ— origin + 1
4.007 Γ— 10⁹⁷(98-digit number)
40071912148057494131…07026338691151667201
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
6
2^5 Γ— origin + 1
8.014 Γ— 10⁹⁷(98-digit number)
80143824296114988263…14052677382303334401
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
7
2^6 Γ— origin + 1
1.602 Γ— 10⁹⁸(99-digit number)
16028764859222997652…28105354764606668801
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
8
2^7 Γ— origin + 1
3.205 Γ— 10⁹⁸(99-digit number)
32057529718445995305…56210709529213337601
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
9
2^8 Γ— origin + 1
6.411 Γ— 10⁹⁸(99-digit number)
64115059436891990610…12421419058426675201
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
10
2^9 Γ— origin + 1
1.282 Γ— 10⁹⁹(100-digit number)
12823011887378398122…24842838116853350401
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 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
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 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 1237115

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 0885bffae77c0d1aa257d3eff38c8df96aaecbe78e38b976934a5194307f12bc

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 #1,237,115 on Chainz β†—
Circulating Supply:57,841,488 XPMΒ·at block #6,824,677 Β· updates every 60s
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