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Block #63,487

2CCLength 8β˜…β˜†β˜†β˜†β˜†

Cunningham Chain of the Second Kind Β· Discovered 7/19/2013, 1:46:16 AM Β· Difficulty 8.9793 Β· 6,736,805 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
cbb98b97ee090d252cc701252269466ad62c8c8efeda31ad5ed2d9e08f8412a9
View on Chainz β†—

Height

#63,487

Difficulty

8.979299

Transactions

1

Size

200 B

Version

2

Bits

08fab356

Nonce

396

Timestamp

7/19/2013, 1:46:16 AM

Confirmations

6,736,805

Merkle Root

d3f07112da4ddb19fe9eaa58765a0b0c8f1a7f12b8f33eac6842e8e0d3334742
Transactions (1)
Coinbased3f07112da4ddb…42e8e0d3334742
1 in β†’ 1 out12.3900 XPM110 B
ALKg2JWW…MSoALsky
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.

1.345 Γ— 10⁹⁡(96-digit number)
13456562136037847840…67579717585402037680
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
1.345 Γ— 10⁹⁡(96-digit number)
13456562136037847840…67579717585402037681
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
2
2^1 Γ— origin + 1
2.691 Γ— 10⁹⁡(96-digit number)
26913124272075695680…35159435170804075361
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
3
2^2 Γ— origin + 1
5.382 Γ— 10⁹⁡(96-digit number)
53826248544151391361…70318870341608150721
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
4
2^3 Γ— origin + 1
1.076 Γ— 10⁹⁢(97-digit number)
10765249708830278272…40637740683216301441
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
5
2^4 Γ— origin + 1
2.153 Γ— 10⁹⁢(97-digit number)
21530499417660556544…81275481366432602881
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
6
2^5 Γ— origin + 1
4.306 Γ— 10⁹⁢(97-digit number)
43060998835321113088…62550962732865205761
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
7
2^6 Γ— origin + 1
8.612 Γ— 10⁹⁢(97-digit number)
86121997670642226177…25101925465730411521
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
8
2^7 Γ— origin + 1
1.722 Γ— 10⁹⁷(98-digit number)
17224399534128445235…50203850931460823041
Verify on FactorDB β†—Wolfram Alpha β†—

What this block proved

The miner who found this block proved the existence of 8 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
CommonChain length 8
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 63487

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 cbb98b97ee090d252cc701252269466ad62c8c8efeda31ad5ed2d9e08f8412a9

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 #63,487 on Chainz β†—
Circulating Supply:57,646,397 XPMΒ·at block #6,800,291 Β· updates every 60s
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