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Home/Chain Registry/Block #1,190,918

Block #1,190,918

2CCLength 10β˜…β˜…β˜†β˜†β˜†

Cunningham Chain of the Second Kind Β· Discovered 8/11/2015, 6:43:55 PM Β· Difficulty 10.8672 Β· 5,648,713 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
e29448eaf5743f881ca52da48c099bfb25a3d9ccccaa76da2a74f2db5a6de5d7
View on Chainz β†—

Difficulty

10.867151

Transactions

2

Size

3.75 KB

Version

2

Bits

0addfda2

Nonce

54,704,450

Timestamp

8/11/2015, 6:43:55 PM

Confirmations

5,648,713

Merkle Root

6ec0762b568a44dc9c64047b35ee974a3e422c0d8ed04b2faab106bcc1362557
Transactions (2)
Coinbasec92678e411475c…61b47459885f13
1 in β†’ 1 out8.5700 XPM116 B
AJCEY9yy…tg97E6zm
38c6051d368a67…8a77d9c169b4ca
24 in β†’ 2 out306.4315 XPM3.55 KB
Adnjte2w…JtsF4ZARAYeGLxtJ…3XFCDFMm
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.

2.899 Γ— 10⁹⁷(98-digit number)
28995499411960604042…43097199029845413120
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
2.899 Γ— 10⁹⁷(98-digit number)
28995499411960604042…43097199029845413121
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
2
2^1 Γ— origin + 1
5.799 Γ— 10⁹⁷(98-digit number)
57990998823921208084…86194398059690826241
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
3
2^2 Γ— origin + 1
1.159 Γ— 10⁹⁸(99-digit number)
11598199764784241616…72388796119381652481
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
4
2^3 Γ— origin + 1
2.319 Γ— 10⁹⁸(99-digit number)
23196399529568483233…44777592238763304961
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
5
2^4 Γ— origin + 1
4.639 Γ— 10⁹⁸(99-digit number)
46392799059136966467…89555184477526609921
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
6
2^5 Γ— origin + 1
9.278 Γ— 10⁹⁸(99-digit number)
92785598118273932934…79110368955053219841
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
7
2^6 Γ— origin + 1
1.855 Γ— 10⁹⁹(100-digit number)
18557119623654786586…58220737910106439681
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
8
2^7 Γ— origin + 1
3.711 Γ— 10⁹⁹(100-digit number)
37114239247309573173…16441475820212879361
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
9
2^8 Γ— origin + 1
7.422 Γ— 10⁹⁹(100-digit number)
74228478494619146347…32882951640425758721
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
10
2^9 Γ— origin + 1
1.484 Γ— 10¹⁰⁰(101-digit number)
14845695698923829269…65765903280851517441
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 1190918

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 e29448eaf5743f881ca52da48c099bfb25a3d9ccccaa76da2a74f2db5a6de5d7

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 #1,190,918 on Chainz β†—
Circulating Supply:57,961,341 XPMΒ·at block #6,839,630 Β· updates every 60s
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